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Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into sh-latest

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Paul Mundt 2011-10-28 14:16:43 +09:00
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2
Documentation/ABI/removed/o2cb
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@ -1,6 +1,6 @@
What: /sys/o2cb symlink
Date: May 2011
KernelVersion: 2.6.40
KernelVersion: 3.0
Contact: ocfs2-devel@oss.oracle.com
Description: This is a symlink: /sys/o2cb to /sys/fs/o2cb. The symlink is
removed when new versions of ocfs2-tools which know to look

2
Documentation/ABI/removed/raw1394
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@ -5,7 +5,7 @@ Description:
/dev/raw1394 was a character device file that allowed low-level
access to FireWire buses. Its major drawbacks were its inability
to implement sensible device security policies, and its low level
of abstraction that required userspace clients do duplicate much
of abstraction that required userspace clients to duplicate much
of the kernel's ieee1394 core functionality.
Replaced by /dev/fw*, i.e. the <linux/firewire-cdev.h> ABI of
firewire-core.

23
Documentation/ABI/testing/evm Normal file
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@ -0,0 +1,23 @@
What: security/evm
Date: March 2011
Contact: Mimi Zohar <zohar@us.ibm.com>
Description:
EVM protects a file's security extended attributes(xattrs)
against integrity attacks. The initial method maintains an
HMAC-sha1 value across the extended attributes, storing the
value as the extended attribute 'security.evm'.
EVM depends on the Kernel Key Retention System to provide it
with a trusted/encrypted key for the HMAC-sha1 operation.
The key is loaded onto the root's keyring using keyctl. Until
EVM receives notification that the key has been successfully
loaded onto the keyring (echo 1 > <securityfs>/evm), EVM
can not create or validate the 'security.evm' xattr, but
returns INTEGRITY_UNKNOWN. Loading the key and signaling EVM
should be done as early as possible. Normally this is done
in the initramfs, which has already been measured as part
of the trusted boot. For more information on creating and
loading existing trusted/encrypted keys, refer to:
Documentation/keys-trusted-encrypted.txt. (A sample dracut
patch, which loads the trusted/encrypted key and enables
EVM, is available from http://linux-ima.sourceforge.net/#EVM.)

8
Documentation/ABI/testing/sysfs-bus-bcma
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@ -1,6 +1,6 @@
What: /sys/bus/bcma/devices/.../manuf
Date: May 2011
KernelVersion: 2.6.40
KernelVersion: 3.0
Contact: Rafał Miłecki <zajec5@gmail.com>
Description:
Each BCMA core has it's manufacturer id. See
@ -8,7 +8,7 @@ Description:
What: /sys/bus/bcma/devices/.../id
Date: May 2011
KernelVersion: 2.6.40
KernelVersion: 3.0
Contact: Rafał Miłecki <zajec5@gmail.com>
Description:
There are a few types of BCMA cores, they can be identified by
@ -16,7 +16,7 @@ Description:
What: /sys/bus/bcma/devices/.../rev
Date: May 2011
KernelVersion: 2.6.40
KernelVersion: 3.0
Contact: Rafał Miłecki <zajec5@gmail.com>
Description:
BCMA cores of the same type can still slightly differ depending
@ -24,7 +24,7 @@ Description:
What: /sys/bus/bcma/devices/.../class
Date: May 2011
KernelVersion: 2.6.40
KernelVersion: 3.0
Contact: Rafał Miłecki <zajec5@gmail.com>
Description:
Each BCMA core is identified by few fields, including class it

46
Documentation/ABI/testing/sysfs-bus-pci-drivers-ehci_hcd Normal file
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@ -0,0 +1,46 @@
What: /sys/bus/pci/drivers/ehci_hcd/.../companion
/sys/bus/usb/devices/usbN/../companion
Date: January 2007
KernelVersion: 2.6.21
Contact: Alan Stern <stern@rowland.harvard.edu>
Description:
PCI-based EHCI USB controllers (i.e., high-speed USB-2.0
controllers) are often implemented along with a set of
"companion" full/low-speed USB-1.1 controllers. When a
high-speed device is plugged in, the connection is routed
to the EHCI controller; when a full- or low-speed device
is plugged in, the connection is routed to the companion
controller.
Sometimes you want to force a high-speed device to connect
at full speed, which can be accomplished by forcing the
connection to be routed to the companion controller.
That's what this file does. Writing a port number to the
file causes connections on that port to be routed to the
companion controller, and writing the negative of a port
number returns the port to normal operation.
For example: To force the high-speed device attached to
port 4 on bus 2 to run at full speed:
echo 4 >/sys/bus/usb/devices/usb2/../companion
To return the port to high-speed operation:
echo -4 >/sys/bus/usb/devices/usb2/../companion
Reading the file gives the list of ports currently forced
to the companion controller.
Note: Some EHCI controllers do not have companions; they
may contain an internal "transaction translator" or they
may be attached directly to a "rate-matching hub". This
mechanism will not work with such controllers. Also, it
cannot be used to force a port on a high-speed hub to
connect at full speed.
Note: When this file was first added, it appeared in a
different sysfs directory. The location given above is
correct for 2.6.35 (and probably several earlier kernel
versions as well).

15
Documentation/ABI/testing/sysfs-bus-usb
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@ -142,3 +142,18 @@ Description:
such devices.
Users:
usb_modeswitch
What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm
Date: September 2011
Contact: Andiry Xu <andiry.xu@amd.com>
Description:
If CONFIG_USB_SUSPEND is set and a USB 2.0 lpm-capable device
is plugged in to a xHCI host which support link PM, it will
perform a LPM test; if the test is passed and host supports
USB2 hardware LPM (xHCI 1.0 feature), USB2 hardware LPM will
be enabled for the device and the USB device directory will
contain a file named power/usb2_hardware_lpm. The file holds
a string value (enable or disable) indicating whether or not
USB2 hardware LPM is enabled for the device. Developer can
write y/Y/1 or n/N/0 to the file to enable/disable the
feature.

16
Documentation/ABI/testing/sysfs-class-backlight-driver-adp8870
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@ -4,8 +4,8 @@ What: /sys/class/backlight/<backlight>/l2_bright_max
What: /sys/class/backlight/<backlight>/l3_office_max
What: /sys/class/backlight/<backlight>/l4_indoor_max
What: /sys/class/backlight/<backlight>/l5_dark_max
Date: Mai 2011
KernelVersion: 2.6.40
Date: May 2011
KernelVersion: 3.0
Contact: device-drivers-devel@blackfin.uclinux.org
Description:
Control the maximum brightness for <ambient light zone>
@ -18,8 +18,8 @@ What: /sys/class/backlight/<backlight>/l2_bright_dim
What: /sys/class/backlight/<backlight>/l3_office_dim
What: /sys/class/backlight/<backlight>/l4_indoor_dim
What: /sys/class/backlight/<backlight>/l5_dark_dim
Date: Mai 2011
KernelVersion: 2.6.40
Date: May 2011
KernelVersion: 3.0
Contact: device-drivers-devel@blackfin.uclinux.org
Description:
Control the dim brightness for <ambient light zone>
@ -29,8 +29,8 @@ Description:
this <ambient light zone>.
What: /sys/class/backlight/<backlight>/ambient_light_level
Date: Mai 2011
KernelVersion: 2.6.40
Date: May 2011
KernelVersion: 3.0
Contact: device-drivers-devel@blackfin.uclinux.org
Description:
Get conversion value of the light sensor.
@ -39,8 +39,8 @@ Description:
8000 (max ambient brightness)
What: /sys/class/backlight/<backlight>/ambient_light_zone
Date: Mai 2011
KernelVersion: 2.6.40
Date: May 2011
KernelVersion: 3.0
Contact: device-drivers-devel@blackfin.uclinux.org
Description:
Get/Set current ambient light zone. Reading returns

52
Documentation/ABI/testing/sysfs-class-devfreq Normal file
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@ -0,0 +1,52 @@
What: /sys/class/devfreq/.../
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
Provide a place in sysfs for the devfreq objects.
This allows accessing various devfreq specific variables.
The name of devfreq object denoted as ... is same as the
name of device using devfreq.
What: /sys/class/devfreq/.../governor
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../governor shows the name of the
governor used by the corresponding devfreq object.
What: /sys/class/devfreq/.../cur_freq
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../cur_freq shows the current
frequency of the corresponding devfreq object.
What: /sys/class/devfreq/.../central_polling
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../central_polling shows whether
the devfreq ojbect is using devfreq-provided central
polling mechanism or not.
What: /sys/class/devfreq/.../polling_interval
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../polling_interval shows and sets
the requested polling interval of the corresponding devfreq
object. The values are represented in ms. If the value is
less than 1 jiffy, it is considered to be 0, which means
no polling. This value is meaningless if the governor is
not polling; thus. If the governor is not using
devfreq-provided central polling
(/sys/class/devfreq/.../central_polling is 0), this value
may be useless.
What: /sys/class/devfreq/.../userspace/set_freq
Date: September 2011
Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
Description:
The /sys/class/devfreq/.../userspace/set_freq shows and
sets the requested frequency for the devfreq object if
userspace governor is in effect.

8
Documentation/ABI/testing/sysfs-class-net-mesh
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@ -22,6 +22,14 @@ Description:
mesh will be fragmented or silently discarded if the
packet size exceeds the outgoing interface MTU.
What: /sys/class/net/<mesh_iface>/mesh/ap_isolation
Date: May 2011
Contact: Antonio Quartulli <ordex@autistici.org>
Description:
Indicates whether the data traffic going from a
wireless client to another wireless client will be
silently dropped.
What: /sys/class/net/<mesh_iface>/mesh/gw_bandwidth
Date: October 2010
Contact: Marek Lindner <lindner_marek@yahoo.de>

13
Documentation/ABI/testing/sysfs-class-scsi_host Normal file
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@ -0,0 +1,13 @@
What: /sys/class/scsi_host/hostX/isci_id
Date: June 2011
Contact: Dave Jiang <dave.jiang@intel.com>
Description:
This file contains the enumerated host ID for the Intel
SCU controller. The Intel(R) C600 Series Chipset SATA/SAS
Storage Control Unit embeds up to two 4-port controllers in
a single PCI device. The controllers are enumerated in order
which usually means the lowest number scsi_host corresponds
with the first controller, but this association is not
guaranteed. The 'isci_id' attribute unambiguously identifies
the controller index: '0' for the first controller,
'1' for the second.

7
Documentation/ABI/testing/sysfs-driver-hid-logitech-lg4ff Normal file
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@ -0,0 +1,7 @@
What: /sys/module/hid_logitech/drivers/hid:logitech/<dev>/range.
Date: July 2011
KernelVersion: 3.2
Contact: Michal Malý <madcatxster@gmail.com>
Description: Display minimum, maximum and current range of the steering
wheel. Writing a value within min and max boundaries sets the
range of the wheel.

72
Documentation/ABI/testing/sysfs-driver-wacom Normal file
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@ -0,0 +1,72 @@
What: /sys/class/hidraw/hidraw*/device/speed
Date: April 2010
Kernel Version: 2.6.35
Contact: linux-bluetooth@vger.kernel.org
Description:
The /sys/class/hidraw/hidraw*/device/speed file controls
reporting speed of Wacom bluetooth tablet. Reading from
this file returns 1 if tablet reports in high speed mode
or 0 otherwise. Writing to this file one of these values
switches reporting speed.
What: /sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/led
Date: August 2011
Contact: linux-input@vger.kernel.org
Description:
Attribute group for control of the status LEDs and the OLEDs.
This attribute group is only available for Intuos 4 M, L,
and XL (with LEDs and OLEDs) and Cintiq 21UX2 (LEDs only).
Therefore its presence implicitly signifies the presence of
said LEDs and OLEDs on the tablet device.
What: /sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/status0_luminance
Date: August 2011
Contact: linux-input@vger.kernel.org
Description:
Writing to this file sets the status LED luminance (1..127)
when the stylus does not touch the tablet surface, and no
button is pressed on the stylus. This luminance level is
normally lower than the level when a button is pressed.
What: /sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/status1_luminance
Date: August 2011
Contact: linux-input@vger.kernel.org
Description:
Writing to this file sets the status LED luminance (1..127)
when the stylus touches the tablet surface, or any button is
pressed on the stylus.
What: /sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/status_led0_select
Date: August 2011
Contact: linux-input@vger.kernel.org
Description:
Writing to this file sets which one of the four (for Intuos 4)
or of the right four (for Cintiq 21UX2) status LEDs is active (0..3).
The other three LEDs on the same side are always inactive.
What: /sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/status_led1_select
Date: September 2011
Contact: linux-input@vger.kernel.org
Description:
Writing to this file sets which one of the left four (for Cintiq 21UX2)
status LEDs is active (0..3). The other three LEDs on the left are always
inactive.
What: /sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/buttons_luminance
Date: August 2011
Contact: linux-input@vger.kernel.org
Description:
Writing to this file sets the overall luminance level (0..15)
of all eight button OLED displays.
What: /sys/bus/usb/devices/<busnum>-<devnum>:<cfg>.<intf>/wacom_led/button<n>_rawimg
Date: August 2011
Contact: linux-input@vger.kernel.org
Description:
When writing a 1024 byte raw image in Wacom Intuos 4
interleaving format to the file, the image shows up on Button N
of the device. The image is a 64x32 pixel 4-bit gray image. The
1024 byte binary is split up into 16x 64 byte chunks. Each 64
byte chunk encodes the image data for two consecutive lines on
the display. The low nibble of each byte contains the first
line, and the high nibble contains the second line.

10
Documentation/ABI/testing/sysfs-wacom
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@ -1,10 +0,0 @@
What: /sys/class/hidraw/hidraw*/device/speed
Date: April 2010
Kernel Version: 2.6.35
Contact: linux-bluetooth@vger.kernel.org
Description:
The /sys/class/hidraw/hidraw*/device/speed file controls
reporting speed of wacom bluetooth tablet. Reading from
this file returns 1 if tablet reports in high speed mode
or 0 otherwise. Writing to this file one of these values
switches reporting speed.

11
Documentation/DocBook/80211.tmpl
View File

@ -433,8 +433,18 @@
Insert notes about VLAN interfaces with hw crypto here or
in the hw crypto chapter.
</para>
<section id="ps-client">
<title>support for powersaving clients</title>
!Pinclude/net/mac80211.h AP support for powersaving clients
</section>
!Finclude/net/mac80211.h ieee80211_get_buffered_bc
!Finclude/net/mac80211.h ieee80211_beacon_get
!Finclude/net/mac80211.h ieee80211_sta_eosp_irqsafe
!Finclude/net/mac80211.h ieee80211_frame_release_type
!Finclude/net/mac80211.h ieee80211_sta_ps_transition
!Finclude/net/mac80211.h ieee80211_sta_ps_transition_ni
!Finclude/net/mac80211.h ieee80211_sta_set_buffered
!Finclude/net/mac80211.h ieee80211_sta_block_awake
</chapter>
<chapter id="multi-iface">
@ -460,7 +470,6 @@
!Finclude/net/mac80211.h sta_notify_cmd
!Finclude/net/mac80211.h ieee80211_find_sta
!Finclude/net/mac80211.h ieee80211_find_sta_by_ifaddr
!Finclude/net/mac80211.h ieee80211_sta_block_awake
</chapter>
<chapter id="hardware-scan-offload">

38
Documentation/DocBook/media/v4l/controls.xml
View File

@ -1455,7 +1455,7 @@ Applicable to the H264 encoder.</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-h264-vui-sar-idc">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_VUI_SAR_IDC</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_video_h264_vui_sar_idc</entry>
</row>
@ -1561,7 +1561,7 @@ Applicable to the H264 encoder.</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-h264-level">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LEVEL</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_video_h264_level</entry>
</row>
@ -1641,7 +1641,7 @@ Possible values are:</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-mpeg4-level">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_LEVEL</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_video_mpeg4_level</entry>
</row>
@ -1689,9 +1689,9 @@ Possible values are:</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-h264-profile">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_PROFILE</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_h264_profile</entry>
<entry>enum&nbsp;v4l2_mpeg_video_h264_profile</entry>
</row>
<row><entry spanname="descr">The profile information for H264.
Applicable to the H264 encoder.
@ -1774,9 +1774,9 @@ Possible values are:</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-mpeg4-profile">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MPEG4_PROFILE</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_mpeg4_profile</entry>
<entry>enum&nbsp;v4l2_mpeg_video_mpeg4_profile</entry>
</row>
<row><entry spanname="descr">The profile information for MPEG4.
Applicable to the MPEG4 encoder.
@ -1820,9 +1820,9 @@ Applicable to the encoder.
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-multi-slice-mode">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_MULTI_SLICE_MODE</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_multi_slice_mode</entry>
<entry>enum&nbsp;v4l2_mpeg_video_multi_slice_mode</entry>
</row>
<row><entry spanname="descr">Determines how the encoder should handle division of frame into slices.
Applicable to the encoder.
@ -1868,9 +1868,9 @@ Applicable to the encoder.</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-h264-loop-filter-mode">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_LOOP_FILTER_MODE</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_h264_loop_filter_mode</entry>
<entry>enum&nbsp;v4l2_mpeg_video_h264_loop_filter_mode</entry>
</row>
<row><entry spanname="descr">Loop filter mode for H264 encoder.
Possible values are:</entry>
@ -1913,9 +1913,9 @@ Applicable to the H264 encoder.</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-h264-entropy-mode">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_H264_ENTROPY_MODE</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_h264_symbol_mode</entry>
<entry>enum&nbsp;v4l2_mpeg_video_h264_entropy_mode</entry>
</row>
<row><entry spanname="descr">Entropy coding mode for H264 - CABAC/CAVALC.
Applicable to the H264 encoder.
@ -2140,9 +2140,9 @@ previous frames. Applicable to the H264 encoder.</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-video-header-mode">
<entry spanname="id"><constant>V4L2_CID_MPEG_VIDEO_HEADER_MODE</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_header_mode</entry>
<entry>enum&nbsp;v4l2_mpeg_video_header_mode</entry>
</row>
<row><entry spanname="descr">Determines whether the header is returned as the first buffer or is
it returned together with the first frame. Applicable to encoders.
@ -2320,9 +2320,9 @@ Valid only when H.264 and macroblock level RC is enabled (<constant>V4L2_CID_MPE
Applicable to the H264 encoder.</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-mfc51-video-frame-skip-mode">
<entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_FRAME_SKIP_MODE</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_mfc51_frame_skip_mode</entry>
<entry>enum&nbsp;v4l2_mpeg_mfc51_video_frame_skip_mode</entry>
</row>
<row><entry spanname="descr">
Indicates in what conditions the encoder should skip frames. If encoding a frame would cause the encoded stream to be larger then
@ -2361,9 +2361,9 @@ the stream will meet tight bandwidth contraints. Applicable to encoders.
</entry>
</row>
<row><entry></entry></row>
<row>
<row id="v4l2-mpeg-mfc51-video-force-frame-type">
<entry spanname="id"><constant>V4L2_CID_MPEG_MFC51_VIDEO_FORCE_FRAME_TYPE</constant>&nbsp;</entry>
<entry>enum&nbsp;v4l2_mpeg_mfc51_force_frame_type</entry>
<entry>enum&nbsp;v4l2_mpeg_mfc51_video_force_frame_type</entry>
</row>
<row><entry spanname="descr">Force a frame type for the next queued buffer. Applicable to encoders.
Possible values are:</entry>

2
Documentation/DocBook/uio-howto.tmpl
View File

@ -529,7 +529,7 @@ memory (e.g. allocated with <function>kmalloc()</function>). There's also
</para></listitem>
<listitem><para>
<varname>unsigned long addr</varname>: Required if the mapping is used.
<varname>phys_addr_t addr</varname>: Required if the mapping is used.
Fill in the address of your memory block. This address is the one that
appears in sysfs.
</para></listitem>

2
Documentation/PCI/pci.txt
View File

@ -314,7 +314,7 @@ from the PCI device config space. Use the values in the pci_dev structure
as the PCI "bus address" might have been remapped to a "host physical"
address by the arch/chip-set specific kernel support.
See Documentation/IO-mapping.txt for how to access device registers
See Documentation/io-mapping.txt for how to access device registers
or device memory.
The device driver needs to call pci_request_region() to verify

2
Documentation/RCU/NMI-RCU.txt
View File

@ -95,7 +95,7 @@ not to return until all ongoing NMI handlers exit. It is therefore safe
to free up the handler's data as soon as synchronize_sched() returns.
Important note: for this to work, the architecture in question must
invoke irq_enter() and irq_exit() on NMI entry and exit, respectively.
invoke nmi_enter() and nmi_exit() on NMI entry and exit, respectively.
Answer to Quick Quiz

110
Documentation/RCU/lockdep-splat.txt Normal file
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@ -0,0 +1,110 @@
Lockdep-RCU was added to the Linux kernel in early 2010
(http://lwn.net/Articles/371986/). This facility checks for some common
misuses of the RCU API, most notably using one of the rcu_dereference()
family to access an RCU-protected pointer without the proper protection.
When such misuse is detected, an lockdep-RCU splat is emitted.
The usual cause of a lockdep-RCU slat is someone accessing an
RCU-protected data structure without either (1) being in the right kind of
RCU read-side critical section or (2) holding the right update-side lock.
This problem can therefore be serious: it might result in random memory
overwriting or worse. There can of course be false positives, this
being the real world and all that.
So let's look at an example RCU lockdep splat from 3.0-rc5, one that
has long since been fixed:
===============================
[ INFO: suspicious RCU usage. ]
-------------------------------
block/cfq-iosched.c:2776 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
3 locks held by scsi_scan_6/1552:
#0: (&shost->scan_mutex){+.+.+.}, at: [<ffffffff8145efca>]
scsi_scan_host_selected+0x5a/0x150
#1: (&eq->sysfs_lock){+.+...}, at: [<ffffffff812a5032>]
elevator_exit+0x22/0x60
#2: (&(&q->__queue_lock)->rlock){-.-...}, at: [<ffffffff812b6233>]
cfq_exit_queue+0x43/0x190
stack backtrace:
Pid: 1552, comm: scsi_scan_6 Not tainted 3.0.0-rc5 #17
Call Trace:
[<ffffffff810abb9b>] lockdep_rcu_dereference+0xbb/0xc0
[<ffffffff812b6139>] __cfq_exit_single_io_context+0xe9/0x120
[<ffffffff812b626c>] cfq_exit_queue+0x7c/0x190
[<ffffffff812a5046>] elevator_exit+0x36/0x60
[<ffffffff812a802a>] blk_cleanup_queue+0x4a/0x60
[<ffffffff8145cc09>] scsi_free_queue+0x9/0x10
[<ffffffff81460944>] __scsi_remove_device+0x84/0xd0
[<ffffffff8145dca3>] scsi_probe_and_add_lun+0x353/0xb10
[<ffffffff817da069>] ? error_exit+0x29/0xb0
[<ffffffff817d98ed>] ? _raw_spin_unlock_irqrestore+0x3d/0x80
[<ffffffff8145e722>] __scsi_scan_target+0x112/0x680
[<ffffffff812c690d>] ? trace_hardirqs_off_thunk+0x3a/0x3c
[<ffffffff817da069>] ? error_exit+0x29/0xb0
[<ffffffff812bcc60>] ? kobject_del+0x40/0x40
[<ffffffff8145ed16>] scsi_scan_channel+0x86/0xb0
[<ffffffff8145f0b0>] scsi_scan_host_selected+0x140/0x150
[<ffffffff8145f149>] do_scsi_scan_host+0x89/0x90
[<ffffffff8145f170>] do_scan_async+0x20/0x160
[<ffffffff8145f150>] ? do_scsi_scan_host+0x90/0x90
[<ffffffff810975b6>] kthread+0xa6/0xb0
[<ffffffff817db154>] kernel_thread_helper+0x4/0x10
[<ffffffff81066430>] ? finish_task_switch+0x80/0x110
[<ffffffff817d9c04>] ? retint_restore_args+0xe/0xe
[<ffffffff81097510>] ? __init_kthread_worker+0x70/0x70
[<ffffffff817db150>] ? gs_change+0xb/0xb
Line 2776 of block/cfq-iosched.c in v3.0-rc5 is as follows:
if (rcu_dereference(ioc->ioc_data) == cic) {
This form says that it must be in a plain vanilla RCU read-side critical
section, but the "other info" list above shows that this is not the
case. Instead, we hold three locks, one of which might be RCU related.
And maybe that lock really does protect this reference. If so, the fix
is to inform RCU, perhaps by changing __cfq_exit_single_io_context() to
take the struct request_queue "q" from cfq_exit_queue() as an argument,
which would permit us to invoke rcu_dereference_protected as follows:
if (rcu_dereference_protected(ioc->ioc_data,
lockdep_is_held(&q->queue_lock)) == cic) {
With this change, there would be no lockdep-RCU splat emitted if this
code was invoked either from within an RCU read-side critical section
or with the ->queue_lock held. In particular, this would have suppressed
the above lockdep-RCU splat because ->queue_lock is held (see #2 in the
list above).
On the other hand, perhaps we really do need an RCU read-side critical
section. In this case, the critical section must span the use of the
return value from rcu_dereference(), or at least until there is some
reference count incremented or some such. One way to handle this is to
add rcu_read_lock() and rcu_read_unlock() as follows:
rcu_read_lock();
if (rcu_dereference(ioc->ioc_data) == cic) {
spin_lock(&ioc->lock);
rcu_assign_pointer(ioc->ioc_data, NULL);
spin_unlock(&ioc->lock);
}
rcu_read_unlock();
With this change, the rcu_dereference() is always within an RCU
read-side critical section, which again would have suppressed the
above lockdep-RCU splat.
But in this particular case, we don't actually deference the pointer
returned from rcu_dereference(). Instead, that pointer is just compared
to the cic pointer, which means that the rcu_dereference() can be replaced
by rcu_access_pointer() as follows:
if (rcu_access_pointer(ioc->ioc_data) == cic) {
Because it is legal to invoke rcu_access_pointer() without protection,
this change would also suppress the above lockdep-RCU splat.

34
Documentation/RCU/lockdep.txt
View File

@ -32,9 +32,27 @@ checking of rcu_dereference() primitives:
srcu_dereference(p, sp):
Check for SRCU read-side critical section.
rcu_dereference_check(p, c):
Use explicit check expression "c". This is useful in
code that is invoked by both readers and updaters.
rcu_dereference_raw(p)
Use explicit check expression "c" along with
rcu_read_lock_held(). This is useful in code that is
invoked by both RCU readers and updaters.
rcu_dereference_bh_check(p, c):
Use explicit check expression "c" along with
rcu_read_lock_bh_held(). This is useful in code that
is invoked by both RCU-bh readers and updaters.
rcu_dereference_sched_check(p, c):
Use explicit check expression "c" along with
rcu_read_lock_sched_held(). This is useful in code that
is invoked by both RCU-sched readers and updaters.
srcu_dereference_check(p, c):
Use explicit check expression "c" along with
srcu_read_lock_held()(). This is useful in code that
is invoked by both SRCU readers and updaters.
rcu_dereference_index_check(p, c):
Use explicit check expression "c", but the caller
must supply one of the rcu_read_lock_held() functions.
This is useful in code that uses RCU-protected arrays
that is invoked by both RCU readers and updaters.
rcu_dereference_raw(p):
Don't check. (Use sparingly, if at all.)
rcu_dereference_protected(p, c):
Use explicit check expression "c", and omit all barriers
@ -48,13 +66,11 @@ checking of rcu_dereference() primitives:
value of the pointer itself, for example, against NULL.
The rcu_dereference_check() check expression can be any boolean
expression, but would normally include one of the rcu_read_lock_held()
family of functions and a lockdep expression. However, any boolean
expression can be used. For a moderately ornate example, consider
the following:
expression, but would normally include a lockdep expression. However,
any boolean expression can be used. For a moderately ornate example,
consider the following:
file = rcu_dereference_check(fdt->fd[fd],
rcu_read_lock_held() ||
lockdep_is_held(&files->file_lock) ||
atomic_read(&files->count) == 1);
@ -62,7 +78,7 @@ This expression picks up the pointer "fdt->fd[fd]" in an RCU-safe manner,
and, if CONFIG_PROVE_RCU is configured, verifies that this expression
is used in:
1. An RCU read-side critical section, or
1. An RCU read-side critical section (implicit), or
2. with files->file_lock held, or
3. on an unshared files_struct.

137
Documentation/RCU/torture.txt
View File

@ -42,7 +42,7 @@ fqs_holdoff Holdoff time (in microseconds) between consecutive calls
fqs_stutter Wait time (in seconds) between consecutive bursts
of calls to force_quiescent_state().
irqreaders Says to invoke RCU readers from irq level. This is currently
irqreader Says to invoke RCU readers from irq level. This is currently
done via timers. Defaults to "1" for variants of RCU that
permit this. (Or, more accurately, variants of RCU that do
-not- permit this know to ignore this variable.)
@ -79,19 +79,68 @@ stutter The length of time to run the test before pausing for this
Specifying "stutter=0" causes the test to run continuously
without pausing, which is the old default behavior.
test_boost Whether or not to test the ability of RCU to do priority
boosting. Defaults to "test_boost=1", which performs
RCU priority-inversion testing only if the selected
RCU implementation supports priority boosting. Specifying
"test_boost=0" never performs RCU priority-inversion
testing. Specifying "test_boost=2" performs RCU
priority-inversion testing even if the selected RCU
implementation does not support RCU priority boosting,
which can be used to test rcutorture's ability to
carry out RCU priority-inversion testing.
test_boost_interval
The number of seconds in an RCU priority-inversion test
cycle. Defaults to "test_boost_interval=7". It is
usually wise for this value to be relatively prime to
the value selected for "stutter".
test_boost_duration
The number of seconds to do RCU priority-inversion testing
within any given "test_boost_interval". Defaults to
"test_boost_duration=4".
test_no_idle_hz Whether or not to test the ability of RCU to operate in
a kernel that disables the scheduling-clock interrupt to
idle CPUs. Boolean parameter, "1" to test, "0" otherwise.
Defaults to omitting this test.
torture_type The type of RCU to test: "rcu" for the rcu_read_lock() API,
"rcu_sync" for rcu_read_lock() with synchronous reclamation,
"rcu_bh" for the rcu_read_lock_bh() API, "rcu_bh_sync" for
rcu_read_lock_bh() with synchronous reclamation, "srcu" for
the "srcu_read_lock()" API, "sched" for the use of
preempt_disable() together with synchronize_sched(),
and "sched_expedited" for the use of preempt_disable()
with synchronize_sched_expedited().
torture_type The type of RCU to test, with string values as follows:
"rcu": rcu_read_lock(), rcu_read_unlock() and call_rcu().
"rcu_sync": rcu_read_lock(), rcu_read_unlock(), and
synchronize_rcu().
"rcu_expedited": rcu_read_lock(), rcu_read_unlock(), and
synchronize_rcu_expedited().
"rcu_bh": rcu_read_lock_bh(), rcu_read_unlock_bh(), and
call_rcu_bh().
"rcu_bh_sync": rcu_read_lock_bh(), rcu_read_unlock_bh(),
and synchronize_rcu_bh().
"rcu_bh_expedited": rcu_read_lock_bh(), rcu_read_unlock_bh(),
and synchronize_rcu_bh_expedited().
"srcu": srcu_read_lock(), srcu_read_unlock() and
synchronize_srcu().
"srcu_expedited": srcu_read_lock(), srcu_read_unlock() and
synchronize_srcu_expedited().
"sched": preempt_disable(), preempt_enable(), and
call_rcu_sched().
"sched_sync": preempt_disable(), preempt_enable(), and
synchronize_sched().
"sched_expedited": preempt_disable(), preempt_enable(), and
synchronize_sched_expedited().
Defaults to "rcu".
verbose Enable debug printk()s. Default is disabled.
@ -100,12 +149,12 @@ OUTPUT
The statistics output is as follows:
rcu-torture: --- Start of test: nreaders=16 stat_interval=0 verbose=0
rcu-torture: rtc: 0000000000000000 ver: 1916 tfle: 0 rta: 1916 rtaf: 0 rtf: 1915
rcu-torture: Reader Pipe: 1466408 9747 0 0 0 0 0 0 0 0 0
rcu-torture: Reader Batch: 1464477 11678 0 0 0 0 0 0 0 0
rcu-torture: Free-Block Circulation: 1915 1915 1915 1915 1915 1915 1915 1915 1915 1915 0
rcu-torture: --- End of test
rcu-torture:--- Start of test: nreaders=16 nfakewriters=4 stat_interval=30 verbose=0 test_no_idle_hz=1 shuffle_interval=3 stutter=5 irqreader=1 fqs_duration=0 fqs_holdoff=0 fqs_stutter=3 test_boost=1/0 test_boost_interval=7 test_boost_duration=4
rcu-torture: rtc: (null) ver: 155441 tfle: 0 rta: 155441 rtaf: 8884 rtf: 155440 rtmbe: 0 rtbke: 0 rtbre: 0 rtbf: 0 rtb: 0 nt: 3055767
rcu-torture: Reader Pipe: 727860534 34213 0 0 0 0 0 0 0 0 0
rcu-torture: Reader Batch: 727877838 17003 0 0 0 0 0 0 0 0 0
rcu-torture: Free-Block Circulation: 155440 155440 155440 155440 155440 155440 155440 155440 155440 155440 0
rcu-torture:--- End of test: SUCCESS: nreaders=16 nfakewriters=4 stat_interval=30 verbose=0 test_no_idle_hz=1 shuffle_interval=3 stutter=5 irqreader=1 fqs_duration=0 fqs_holdoff=0 fqs_stutter=3 test_boost=1/0 test_boost_interval=7 test_boost_duration=4
The command "dmesg | grep torture:" will extract this information on
most systems. On more esoteric configurations, it may be necessary to
@ -113,26 +162,55 @@ use other commands to access the output of the printk()s used by
the RCU torture test. The printk()s use KERN_ALERT, so they should
be evident. ;-)
The first and last lines show the rcutorture module parameters, and the
last line shows either "SUCCESS" or "FAILURE", based on rcutorture's
automatic determination as to whether RCU operated correctly.
The entries are as follows:
o "rtc": The hexadecimal address of the structure currently visible
to readers.
o "ver": The number of times since boot that the rcutw writer task
o "ver": The number of times since boot that the RCU writer task
has changed the structure visible to readers.
o "tfle": If non-zero, indicates that the "torture freelist"
containing structure to be placed into the "rtc" area is empty.
containing structures to be placed into the "rtc" area is empty.
This condition is important, since it can fool you into thinking
that RCU is working when it is not. :-/
o "rta": Number of structures allocated from the torture freelist.
o "rtaf": Number of allocations from the torture freelist that have
failed due to the list being empty.
failed due to the list being empty. It is not unusual for this
to be non-zero, but it is bad for it to be a large fraction of
the value indicated by "rta".
o "rtf": Number of frees into the torture freelist.
o "rtmbe": A non-zero value indicates that rcutorture believes that
rcu_assign_pointer() and rcu_dereference() are not working
correctly. This value should be zero.
o "rtbke": rcutorture was unable to create the real-time kthreads
used to force RCU priority inversion. This value should be zero.
o "rtbre": Although rcutorture successfully created the kthreads
used to force RCU priority inversion, it was unable to set them
to the real-time priority level of 1. This value should be zero.
o "rtbf": The number of times that RCU priority boosting failed
to resolve RCU priority inversion.
o "rtb": The number of times that rcutorture attempted to force
an RCU priority inversion condition. If you are testing RCU
priority boosting via the "test_boost" module parameter, this
value should be non-zero.
o "nt": The number of times rcutorture ran RCU read-side code from
within a timer handler. This value should be non-zero only
if you specified the "irqreader" module parameter.
o "Reader Pipe": Histogram of "ages" of structures seen by readers.
If any entries past the first two are non-zero, RCU is broken.
And rcutorture prints the error flag string "!!!" to make sure
@ -162,26 +240,15 @@ o "Free-Block Circulation": Shows the number of torture structures
somehow gets incremented farther than it should.
Different implementations of RCU can provide implementation-specific
additional information. For example, SRCU provides the following:
additional information. For example, SRCU provides the following
additional line:
srcu-torture: rtc: f8cf46a8 ver: 355 tfle: 0 rta: 356 rtaf: 0 rtf: 346 rtmbe: 0
srcu-torture: Reader Pipe: 559738 939 0 0 0 0 0 0 0 0 0
srcu-torture: Reader Batch: 560434 243 0 0 0 0 0 0 0 0
srcu-torture: Free-Block Circulation: 355 354 353 352 351 350 349 348 347 346 0
srcu-torture: per-CPU(idx=1): 0(0,1) 1(0,1) 2(0,0) 3(0,1)
The first four lines are similar to those for RCU. The last line shows
the per-CPU counter state. The numbers in parentheses are the values
of the "old" and "current" counters for the corresponding CPU. The
"idx" value maps the "old" and "current" values to the underlying array,
and is useful for debugging.
Similarly, sched_expedited RCU provides the following:
sched_expedited-torture: rtc: d0000000016c1880 ver: 1090796 tfle: 0 rta: 1090796 rtaf: 0 rtf: 1090787 rtmbe: 0 nt: 27713319
sched_expedited-torture: Reader Pipe: 12660320201 95875 0 0 0 0 0 0 0 0 0
sched_expedited-torture: Reader Batch: 12660424885 0 0 0 0 0 0 0 0 0 0
sched_expedited-torture: Free-Block Circulation: 1090795 1090795 1090794 1090793 1090792 1090791 1090790 1090789 1090788 1090787 0
This line shows the per-CPU counter state. The numbers in parentheses are
the values of the "old" and "current" counters for the corresponding CPU.
The "idx" value maps the "old" and "current" values to the underlying
array, and is useful for debugging.
USAGE

38
Documentation/RCU/trace.txt
View File

@ -33,23 +33,23 @@ rcu/rcuboost:
The output of "cat rcu/rcudata" looks as follows:
rcu_sched:
0 c=20972 g=20973 pq=1 pqc=20972 qp=0 dt=545/1/0 df=50 of=0 ri=0 ql=163 qs=NRW. kt=0/W/0 ktl=ebc3 b=10 ci=153737 co=0 ca=0
1 c=20972 g=20973 pq=1 pqc=20972 qp=0 dt=967/1/0 df=58 of=0 ri=0 ql=634 qs=NRW. kt=0/W/1 ktl=58c b=10 ci=191037 co=0 ca=0
2 c=20972 g=20973 pq=1 pqc=20972 qp=0 dt=1081/1/0 df=175 of=0 ri=0 ql=74 qs=N.W. kt=0/W/2 ktl=da94 b=10 ci=75991 co=0 ca=0
3 c=20942 g=20943 pq=1 pqc=20942 qp=1 dt=1846/0/0 df=404 of=0 ri=0 ql=0 qs=.... kt=0/W/3 ktl=d1cd b=10 ci=72261 co=0 ca=0
4 c=20972 g=20973 pq=1 pqc=20972 qp=0 dt=369/1/0 df=83 of=0 ri=0 ql=48 qs=N.W. kt=0/W/4 ktl=e0e7 b=10 ci=128365 co=0 ca=0
5 c=20972 g=20973 pq=1 pqc=20972 qp=0 dt=381/1/0 df=64 of=0 ri=0 ql=169 qs=NRW. kt=0/W/5 ktl=fb2f b=10 ci=164360 co=0 ca=0
6 c=20972 g=20973 pq=1 pqc=20972 qp=0 dt=1037/1/0 df=183 of=0 ri=0 ql=62 qs=N.W. kt=0/W/6 ktl=d2ad b=10 ci=65663 co=0 ca=0
7 c=20897 g=20897 pq=1 pqc=20896 qp=0 dt=1572/0/0 df=382 of=0 ri=0 ql=0 qs=.... kt=0/W/7 ktl=cf15 b=10 ci=75006 co=0 ca=0
0 c=20972 g=20973 pq=1 pgp=20973 qp=0 dt=545/1/0 df=50 of=0 ri=0 ql=163 qs=NRW. kt=0/W/0 ktl=ebc3 b=10 ci=153737 co=0 ca=0
1 c=20972 g=20973 pq=1 pgp=20973 qp=0 dt=967/1/0 df=58 of=0 ri=0 ql=634 qs=NRW. kt=0/W/1 ktl=58c b=10 ci=191037 co=0 ca=0
2 c=20972 g=20973 pq=1 pgp=20973 qp=0 dt=1081/1/0 df=175 of=0 ri=0 ql=74 qs=N.W. kt=0/W/2 ktl=da94 b=10 ci=75991 co=0 ca=0
3 c=20942 g=20943 pq=1 pgp=20942 qp=1 dt=1846/0/0 df=404 of=0 ri=0 ql=0 qs=.... kt=0/W/3 ktl=d1cd b=10 ci=72261 co=0 ca=0
4 c=20972 g=20973 pq=1 pgp=20973 qp=0 dt=369/1/0 df=83 of=0 ri=0 ql=48 qs=N.W. kt=0/W/4 ktl=e0e7 b=10 ci=128365 co=0 ca=0
5 c=20972 g=20973 pq=1 pgp=20973 qp=0 dt=381/1/0 df=64 of=0 ri=0 ql=169 qs=NRW. kt=0/W/5 ktl=fb2f b=10 ci=164360 co=0 ca=0
6 c=20972 g=20973 pq=1 pgp=20973 qp=0 dt=1037/1/0 df=183 of=0 ri=0 ql=62 qs=N.W. kt=0/W/6 ktl=d2ad b=10 ci=65663 co=0 ca=0
7 c=20897 g=20897 pq=1 pgp=20896 qp=0 dt=1572/0/0 df=382 of=0 ri=0 ql=0 qs=.... kt=0/W/7 ktl=cf15 b=10 ci=75006 co=0 ca=0
rcu_bh:
0 c=1480 g=1480 pq=1 pqc=1479 qp=0 dt=545/1/0 df=6 of=0 ri=1 ql=0 qs=.... kt=0/W/0 ktl=ebc3 b=10 ci=0 co=0 ca=0
1 c=1480 g=1480 pq=1 pqc=1479 qp=0 dt=967/1/0 df=3 of=0 ri=1 ql=0 qs=.... kt=0/W/1 ktl=58c b=10 ci=151 co=0 ca=0
2 c=1480 g=1480 pq=1 pqc=1479 qp=0 dt=1081/1/0 df=6 of=0 ri=1 ql=0 qs=.... kt=0/W/2 ktl=da94 b=10 ci=0 co=0 ca=0
3 c=1480 g=1480 pq=1 pqc=1479 qp=0 dt=1846/0/0 df=8 of=0 ri=1 ql=0 qs=.... kt=0/W/3 ktl=d1cd b=10 ci=0 co=0 ca=0
4 c=1480 g=1480 pq=1 pqc=1479 qp=0 dt=369/1/0 df=6 of=0 ri=1 ql=0 qs=.... kt=0/W/4 ktl=e0e7 b=10 ci=0 co=0 ca=0
5 c=1480 g=1480 pq=1 pqc=1479 qp=0 dt=381/1/0 df=4 of=0 ri=1 ql=0 qs=.... kt=0/W/5 ktl=fb2f b=10 ci=0 co=0 ca=0
6 c=1480 g=1480 pq=1 pqc=1479 qp=0 dt=1037/1/0 df=6 of=0 ri=1 ql=0 qs=.... kt=0/W/6 ktl=d2ad b=10 ci=0 co=0 ca=0
7 c=1474 g=1474 pq=1 pqc=1473 qp=0 dt=1572/0/0 df=8 of=0 ri=1 ql=0 qs=.... kt=0/W/7 ktl=cf15 b=10 ci=0 co=0 ca=0
0 c=1480 g=1480 pq=1 pgp=1480 qp=0 dt=545/1/0 df=6 of=0 ri=1 ql=0 qs=.... kt=0/W/0 ktl=ebc3 b=10 ci=0 co=0 ca=0
1 c=1480 g=1480 pq=1 pgp=1480 qp=0 dt=967/1/0 df=3 of=0 ri=1 ql=0 qs=.... kt=0/W/1 ktl=58c b=10 ci=151 co=0 ca=0
2 c=1480 g=1480 pq=1 pgp=1480 qp=0 dt=1081/1/0 df=6 of=0 ri=1 ql=0 qs=.... kt=0/W/2 ktl=da94 b=10 ci=0 co=0 ca=0
3 c=1480 g=1480 pq=1 pgp=1480 qp=0 dt=1846/0/0 df=8 of=0 ri=1 ql=0 qs=.... kt=0/W/3 ktl=d1cd b=10 ci=0 co=0 ca=0
4 c=1480 g=1480 pq=1 pgp=1480 qp=0 dt=369/1/0 df=6 of=0 ri=1 ql=0 qs=.... kt=0/W/4 ktl=e0e7 b=10 ci=0 co=0 ca=0
5 c=1480 g=1480 pq=1 pgp=1480 qp=0 dt=381/1/0 df=4 of=0 ri=1 ql=0 qs=.... kt=0/W/5 ktl=fb2f b=10 ci=0 co=0 ca=0
6 c=1480 g=1480 pq=1 pgp=1480 qp=0 dt=1037/1/0 df=6 of=0 ri=1 ql=0 qs=.... kt=0/W/6 ktl=d2ad b=10 ci=0 co=0 ca=0
7 c=1474 g=1474 pq=1 pgp=1473 qp=0 dt=1572/0/0 df=8 of=0 ri=1 ql=0 qs=.... kt=0/W/7 ktl=cf15 b=10 ci=0 co=0 ca=0
The first section lists the rcu_data structures for rcu_sched, the second
for rcu_bh. Note that CONFIG_TREE_PREEMPT_RCU kernels will have an
@ -84,7 +84,7 @@ o "pq" indicates that this CPU has passed through a quiescent state
CPU has not yet reported that fact, (2) some other CPU has not
yet reported for this grace period, or (3) both.
o "pqc" indicates which grace period the last-observed quiescent
o "pgp" indicates which grace period the last-observed quiescent
state for this CPU corresponds to. This is important for handling
the race between CPU 0 reporting an extended dynticks-idle
quiescent state for CPU 1 and CPU 1 suddenly waking up and
@ -184,10 +184,14 @@ o "kt" is the per-CPU kernel-thread state. The digit preceding
The number after the final slash is the CPU that the kthread
is actually running on.
This field is displayed only for CONFIG_RCU_BOOST kernels.
o "ktl" is the low-order 16 bits (in hexadecimal) of the count of
the number of times that this CPU's per-CPU kthread has gone
through its loop servicing invoke_rcu_cpu_kthread() requests.
This field is displayed only for CONFIG_RCU_BOOST kernels.
o "b" is the batch limit for this CPU. If more than this number
of RCU callbacks is ready to invoke, then the remainder will
be deferred.

2
Documentation/blackfin/bfin-gpio-notes.txt
View File

@ -1,5 +1,5 @@
/*
* File: Documentation/blackfin/bfin-gpio-note.txt
* File: Documentation/blackfin/bfin-gpio-notes.txt
* Based on:
* Author:
*

2
Documentation/block/biodoc.txt
View File

@ -186,7 +186,7 @@ a virtual address mapping (unlike the earlier scheme of virtual address
do not have a corresponding kernel virtual address space mapping) and
low-memory pages.
Note: Please refer to Documentation/PCI/PCI-DMA-mapping.txt for a discussion
Note: Please refer to Documentation/DMA-API-HOWTO.txt for a discussion
on PCI high mem DMA aspects and mapping of scatter gather lists, and support
for 64 bit PCI.

2
Documentation/bus-virt-phys-mapping.txt
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@ -1,6 +1,6 @@
[ NOTE: The virt_to_bus() and bus_to_virt() functions have been
superseded by the functionality provided by the PCI DMA interface
(see Documentation/PCI/PCI-DMA-mapping.txt). They continue
(see Documentation/DMA-API-HOWTO.txt). They continue
to be documented below for historical purposes, but new code
must not use them. --davidm 00/12/12 ]

2
Documentation/cdrom/packet-writing.txt
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@ -109,7 +109,7 @@ this interface. (see http://tom.ist-im-web.de/download/pktcdvd )
For a description of the sysfs interface look into the file:
Documentation/ABI/testing/sysfs-block-pktcdvd
Documentation/ABI/testing/sysfs-class-pktcdvd
Using the pktcdvd debugfs interface

85
Documentation/cgroups/memory.txt
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@ -380,7 +380,7 @@ will be charged as a new owner of it.
5.2 stat file
5.2.1 memory.stat file includes following statistics
memory.stat file includes following statistics
# per-memory cgroup local status
cache - # of bytes of page cache memory.
@ -438,89 +438,6 @@ Note:
file_mapped is accounted only when the memory cgroup is owner of page
cache.)
5.2.2 memory.vmscan_stat
memory.vmscan_stat includes statistics information for memory scanning and
freeing, reclaiming. The statistics shows memory scanning information since
memory cgroup creation and can be reset to 0 by writing 0 as
#echo 0 > ../memory.vmscan_stat
This file contains following statistics.
[param]_[file_or_anon]_pages_by_[reason]_[under_heararchy]
[param]_elapsed_ns_by_[reason]_[under_hierarchy]
For example,
scanned_file_pages_by_limit indicates the number of scanned
file pages at vmscan.
Now, 3 parameters are supported
scanned - the number of pages scanned by vmscan
rotated - the number of pages activated at vmscan
freed - the number of pages freed by vmscan
If "rotated" is high against scanned/freed, the memcg seems busy.
Now, 2 reason are supported
limit - the memory cgroup's limit
system - global memory pressure + softlimit
(global memory pressure not under softlimit is not handled now)
When under_hierarchy is added in the tail, the number indicates the
total memcg scan of its children and itself.
elapsed_ns is a elapsed time in nanosecond. This may include sleep time
and not indicates CPU usage. So, please take this as just showing
latency.
Here is an example.
# cat /cgroup/memory/A/memory.vmscan_stat
scanned_pages_by_limit 9471864
scanned_anon_pages_by_limit 6640629
scanned_file_pages_by_limit 2831235
rotated_pages_by_limit 4243974
rotated_anon_pages_by_limit 3971968
rotated_file_pages_by_limit 272006
freed_pages_by_limit 2318492
freed_anon_pages_by_limit 962052
freed_file_pages_by_limit 1356440
elapsed_ns_by_limit 351386416101
scanned_pages_by_system 0
scanned_anon_pages_by_system 0
scanned_file_pages_by_system 0
rotated_pages_by_system 0
rotated_anon_pages_by_system 0
rotated_file_pages_by_system 0
freed_pages_by_system 0
freed_anon_pages_by_system 0
freed_file_pages_by_system 0
elapsed_ns_by_system 0
scanned_pages_by_limit_under_hierarchy 9471864
scanned_anon_pages_by_limit_under_hierarchy 6640629
scanned_file_pages_by_limit_under_hierarchy 2831235
rotated_pages_by_limit_under_hierarchy 4243974
rotated_anon_pages_by_limit_under_hierarchy 3971968
rotated_file_pages_by_limit_under_hierarchy 272006
freed_pages_by_limit_under_hierarchy 2318492
freed_anon_pages_by_limit_under_hierarchy 962052
freed_file_pages_by_limit_under_hierarchy 1356440
elapsed_ns_by_limit_under_hierarchy 351386416101
scanned_pages_by_system_under_hierarchy 0
scanned_anon_pages_by_system_under_hierarchy 0
scanned_file_pages_by_system_under_hierarchy 0
rotated_pages_by_system_under_hierarchy 0
rotated_anon_pages_by_system_under_hierarchy 0
rotated_file_pages_by_system_under_hierarchy 0
freed_pages_by_system_under_hierarchy 0
freed_anon_pages_by_system_under_hierarchy 0
freed_file_pages_by_system_under_hierarchy 0
elapsed_ns_by_system_under_hierarchy 0
5.3 swappiness
Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.

2
Documentation/cpu-freq/governors.txt
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@ -132,7 +132,7 @@ The sampling rate is limited by the HW transition latency:
transition_latency * 100
Or by kernel restrictions:
If CONFIG_NO_HZ is set, the limit is 10ms fixed.
If CONFIG_NO_HZ is not set or no_hz=off boot parameter is used, the
If CONFIG_NO_HZ is not set or nohz=off boot parameter is used, the
limits depend on the CONFIG_HZ option:
HZ=1000: min=20000us (20ms)
HZ=250: min=80000us (80ms)

2
Documentation/development-process/4.Coding
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@ -278,7 +278,7 @@ enabled, a configurable percentage of memory allocations will be made to
fail; these failures can be restricted to a specific range of code.
Running with fault injection enabled allows the programmer to see how the
code responds when things go badly. See
Documentation/fault-injection/fault-injection.text for more information on
Documentation/fault-injection/fault-injection.txt for more information on
how to use this facility.
Other kinds of errors can be found with the "sparse" static analysis tool.

44
Documentation/devicetree/bindings/arm/l2cc.txt Normal file
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@ -0,0 +1,44 @@
* ARM L2 Cache Controller
ARM cores often have a separate level 2 cache controller. There are various
implementations of the L2 cache controller with compatible programming models.
The ARM L2 cache representation in the device tree should be done as follows:
Required properties:
- compatible : should be one of:
"arm,pl310-cache"
"arm,l220-cache"
"arm,l210-cache"
- cache-unified : Specifies the cache is a unified cache.
- cache-level : Should be set to 2 for a level 2 cache.
- reg : Physical base address and size of cache controller's memory mapped
registers.
Optional properties:
- arm,data-latency : Cycles of latency for Data RAM accesses. Specifies 3 cells of
read, write and setup latencies. Minimum valid values are 1. Controllers
without setup latency control should use a value of 0.
- arm,tag-latency : Cycles of latency for Tag RAM accesses. Specifies 3 cells of
read, write and setup latencies. Controllers without setup latency control
should use 0. Controllers without separate read and write Tag RAM latency
values should only use the first cell.
- arm,dirty-latency : Cycles of latency for Dirty RAMs. This is a single cell.
- arm,filter-ranges : <start length> Starting address and length of window to
filter. Addresses in the filter window are directed to the M1 port. Other
addresses will go to the M0 port.
- interrupts : 1 combined interrupt.
Example:
L2: cache-controller {
compatible = "arm,pl310-cache";
reg = <0xfff12000 0x1000>;
arm,data-latency = <1 1 1>;
arm,tag-latency = <2 2 2>;
arm,filter-latency = <0x80000000 0x8000000>;
cache-unified;
cache-level = <2>;
interrupts = <45>;
};

4
Documentation/devicetree/bindings/arm/primecell.txt
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@ -6,7 +6,9 @@ driver matching.
Required properties:
- compatible : should be a specific value for peripheral and "arm,primecell"
- compatible : should be a specific name for the peripheral and
"arm,primecell". The specific name will match the ARM
engineering name for the logic block in the form: "arm,pl???"
Optional properties:

2
Documentation/devicetree/bindings/gpio/led.txt
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@ -8,7 +8,7 @@ node's name represents the name of the corresponding LED.
LED sub-node properties:
- gpios : Should specify the LED's GPIO, see "Specifying GPIO information
for devices" in Documentation/powerpc/booting-without-of.txt. Active
for devices" in Documentation/devicetree/booting-without-of.txt. Active
low LEDs should be indicated using flags in the GPIO specifier.
- label : (optional) The label for this LED. If omitted, the label is
taken from the node name (excluding the unit address).

10
Documentation/devicetree/bindings/gpio/pl061-gpio.txt Normal file
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@ -0,0 +1,10 @@
ARM PL061 GPIO controller
Required properties:
- compatible : "arm,pl061", "arm,primecell"
- #gpio-cells : Should be two. The first cell is the pin number and the
second cell is used to specify optional parameters:
- bit 0 specifies polarity (0 for normal, 1 for inverted)
- gpio-controller : Marks the device node as a GPIO controller.
- interrupts : Interrupt mapping for GPIO IRQ.

63
Documentation/devicetree/bindings/net/can/fsl-flexcan.txt
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@ -1,61 +1,24 @@
CAN Device Tree Bindings
------------------------
2011 Freescale Semiconductor, Inc.
Flexcan CAN contoller on Freescale's ARM and PowerPC system-on-a-chip (SOC).
fsl,flexcan-v1.0 nodes
-----------------------
In addition to the required compatible-, reg- and interrupt-properties, you can
also specify which clock source shall be used for the controller.
Required properties:
CPI Clock- Can Protocol Interface Clock
This CLK_SRC bit of CTRL(control register) selects the clock source to
the CAN Protocol Interface(CPI) to be either the peripheral clock
(driven by the PLL) or the crystal oscillator clock. The selected clock
is the one fed to the prescaler to generate the Serial Clock (Sclock).
The PRESDIV field of CTRL(control register) controls a prescaler that
generates the Serial Clock (Sclock), whose period defines the
time quantum used to compose the CAN waveform.
- compatible : Should be "fsl,<processor>-flexcan"
Can Engine Clock Source
There are two sources for CAN clock
- Platform Clock It represents the bus clock
- Oscillator Clock
An implementation should also claim any of the following compatibles
that it is fully backwards compatible with:
Peripheral Clock (PLL)
--------------
|
--------- -------------
| |CPI Clock | Prescaler | Sclock
| |---------------->| (1.. 256) |------------>
--------- -------------
| |
-------------- ---------------------CLK_SRC
Oscillator Clock
- fsl,p1010-flexcan
- fsl,flexcan-clock-source : CAN Engine Clock Source.This property selects
the peripheral clock. PLL clock is fed to the
prescaler to generate the Serial Clock (Sclock).
Valid values are "oscillator" and "platform"
"oscillator": CAN engine clock source is oscillator clock.
"platform" The CAN engine clock source is the bus clock
(platform clock).
- reg : Offset and length of the register set for this device
- interrupts : Interrupt tuple for this device
- clock-frequency : The oscillator frequency driving the flexcan device
- fsl,flexcan-clock-divider : for the reference and system clock, an additional
clock divider can be specified.
- clock-frequency: frequency required to calculate the bitrate for FlexCAN.
Example:
Note:
- v1.0 of flexcan-v1.0 represent the IP block version for P1010 SOC.
- P1010 does not have oscillator as the Clock Source.So the default
Clock Source is platform clock.
Examples:
can0@1c000 {
compatible = "fsl,flexcan-v1.0";
can@1c000 {
compatible = "fsl,p1010-flexcan";
reg = <0x1c000 0x1000>;
interrupts = <48 0x2>;
interrupt-parent = <&mpic>;
fsl,flexcan-clock-source = "platform";
fsl,flexcan-clock-divider = <2>;
clock-frequency = <fixed by u-boot>;
clock-frequency = <200000000>; // filled in by bootloader
};

38
Documentation/devicetree/bindings/net/smsc911x.txt Normal file
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@ -0,0 +1,38 @@
* Smart Mixed-Signal Connectivity (SMSC) LAN911x/912x Controller
Required properties:
- compatible : Should be "smsc,lan<model>", "smsc,lan9115"
- reg : Address and length of the io space for SMSC LAN
- interrupts : Should contain SMSC LAN interrupt line
- interrupt-parent : Should be the phandle for the interrupt controller
that services interrupts for this device
- phy-mode : String, operation mode of the PHY interface.
Supported values are: "mii", "gmii", "sgmii", "tbi", "rmii",
"rgmii", "rgmii-id", "rgmii-rxid", "rgmii-txid", "rtbi", "smii".
Optional properties:
- reg-shift : Specify the quantity to shift the register offsets by
- reg-io-width : Specify the size (in bytes) of the IO accesses that
should be performed on the device. Valid value for SMSC LAN is
2 or 4. If it's omitted or invalid, the size would be 2.
- smsc,irq-active-high : Indicates the IRQ polarity is active-high
- smsc,irq-push-pull : Indicates the IRQ type is push-pull
- smsc,force-internal-phy : Forces SMSC LAN controller to use
internal PHY
- smsc,force-external-phy : Forces SMSC LAN controller to use
external PHY
- smsc,save-mac-address : Indicates that mac address needs to be saved
before resetting the controller
- local-mac-address : 6 bytes, mac address
Examples:
lan9220@f4000000 {
compatible = "smsc,lan9220", "smsc,lan9115";
reg = <0xf4000000 0x2000000>;
phy-mode = "mii";
interrupt-parent = <&gpio1>;
interrupts = <31>;
reg-io-width = <4>;
smsc,irq-push-pull;
};

31
Documentation/devicetree/bindings/serial/rs485.txt Normal file
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@ -0,0 +1,31 @@
* RS485 serial communications
The RTS signal is capable of automatically controlling line direction for
the built-in half-duplex mode.
The properties described hereafter shall be given to a half-duplex capable
UART node.
Required properties:
- rs485-rts-delay: prop-encoded-array <a b> where:
* a is the delay beteween rts signal and beginning of data sent in milliseconds.
it corresponds to the delay before sending data.
* b is the delay between end of data sent and rts signal in milliseconds
it corresponds to the delay after sending data and actual release of the line.
Optional properties:
- linux,rs485-enabled-at-boot-time: empty property telling to enable the rs485
feature at boot time. It can be disabled later with proper ioctl.
- rs485-rx-during-tx: empty property that enables the receiving of data even
whilst sending data.
RS485 example for Atmel USART:
usart0: serial@fff8c000 {
compatible = "atmel,at91sam9260-usart";
reg = <0xfff8c000 0x4000>;
interrupts = <7>;
atmel,use-dma-rx;
atmel,use-dma-tx;
linux,rs485-enabled-at-boot-time;
rs485-rts-delay = <0 200>; // in milliseconds
};

12
Documentation/devicetree/bindings/spi/spi_pl022.txt Normal file
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@ -0,0 +1,12 @@
ARM PL022 SPI controller
Required properties:
- compatible : "arm,pl022", "arm,primecell"
- reg : Offset and length of the register set for the device
- interrupts : Should contain SPI controller interrupt
Optional properties:
- cs-gpios : should specify GPIOs used for chipselects.
The gpios will be referred to as reg = <index> in the SPI child nodes.
If unspecified, a single SPI device without a chip select can be used.

27
Documentation/devicetree/bindings/tty/serial/atmel-usart.txt Normal file
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@ -0,0 +1,27 @@
* Atmel Universal Synchronous Asynchronous Receiver/Transmitter (USART)
Required properties:
- compatible: Should be "atmel,<chip>-usart"
The compatible <chip> indicated will be the first SoC to support an
additional mode or an USART new feature.
- reg: Should contain registers location and length
- interrupts: Should contain interrupt
Optional properties:
- atmel,use-dma-rx: use of PDC or DMA for receiving data
- atmel,use-dma-tx: use of PDC or DMA for transmitting data
<chip> compatible description:
- at91rm9200: legacy USART support
- at91sam9260: generic USART implementation for SAM9 SoCs
Example:
usart0: serial@fff8c000 {
compatible = "atmel,at91sam9260-usart";
reg = <0xfff8c000 0x4000>;
interrupts = <7>;
atmel,use-dma-rx;
atmel,use-dma-tx;
};

25
Documentation/devicetree/bindings/tty/serial/snps-dw-apb-uart.txt Normal file
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@ -0,0 +1,25 @@
* Synopsys DesignWare ABP UART
Required properties:
- compatible : "snps,dw-apb-uart"
- reg : offset and length of the register set for the device.
- interrupts : should contain uart interrupt.
- clock-frequency : the input clock frequency for the UART.
Optional properties:
- reg-shift : quantity to shift the register offsets by. If this property is
not present then the register offsets are not shifted.
- reg-io-width : the size (in bytes) of the IO accesses that should be
performed on the device. If this property is not present then single byte
accesses are used.
Example:
uart@80230000 {
compatible = "snps,dw-apb-uart";
reg = <0x80230000 0x100>;
clock-frequency = <3686400>;
interrupts = <10>;
reg-shift = <2>;
reg-io-width = <4>;
};

40
Documentation/devicetree/bindings/vendor-prefixes.txt Normal file
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@ -0,0 +1,40 @@
Device tree binding vendor prefix registry. Keep list in alphabetical order.
This isn't an exhaustive list, but you should add new prefixes to it before
using them to avoid name-space collisions.
adi Analog Devices, Inc.
amcc Applied Micro Circuits Corporation (APM, formally AMCC)
apm Applied Micro Circuits Corporation (APM)
arm ARM Ltd.
atmel Atmel Corporation
chrp Common Hardware Reference Platform
dallas Maxim Integrated Products (formerly Dallas Semiconductor)
denx Denx Software Engineering
epson Seiko Epson Corp.
est ESTeem Wireless Modems
fsl Freescale Semiconductor
GEFanuc GE Fanuc Intelligent Platforms Embedded Systems, Inc.
gef GE Fanuc Intelligent Platforms Embedded Systems, Inc.
hp Hewlett Packard
ibm International Business Machines (IBM)
idt Integrated Device Technologies, Inc.
intercontrol Inter Control Group
linux Linux-specific binding
marvell Marvell Technology Group Ltd.
maxim Maxim Integrated Products
mosaixtech Mosaix Technologies, Inc.
national National Semiconductor
nintendo Nintendo
nvidia NVIDIA
nxp NXP Semiconductors
powervr Imagination Technologies
qcom Qualcomm, Inc.
ramtron Ramtron International
samsung Samsung Semiconductor
schindler Schindler
simtek
sirf SiRF Technology, Inc.
stericsson ST-Ericsson
ti Texas Instruments
xlnx Xilinx

4
Documentation/driver-model/binding.txt
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@ -48,10 +48,6 @@ devclass_add_device is called to enumerate the device within the class
and actually register it with the class, which happens with the
class's register_dev callback.
NOTE: The device class structures and core routines to manipulate them
are not in the mainline kernel, so the discussion is still a bit
speculative.
Driver
~~~~~~

65
Documentation/driver-model/device.txt
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@ -45,33 +45,52 @@ struct device_attribute {
const char *buf, size_t count);
};
Attributes of devices can be exported via drivers using a simple
procfs-like interface.
Attributes of devices can be exported by a device driver through sysfs.
Please see Documentation/filesystems/sysfs.txt for more information
on how sysfs works.
As explained in Documentation/kobject.txt, device attributes must be be
created before the KOBJ_ADD uevent is generated. The only way to realize
that is by defining an attribute group.
Attributes are declared using a macro called DEVICE_ATTR:
#define DEVICE_ATTR(name,mode,show,store)
Example:
DEVICE_ATTR(power,0644,show_power,store_power);
static DEVICE_ATTR(type, 0444, show_type, NULL);
static DEVICE_ATTR(power, 0644, show_power, store_power);
This declares a structure of type struct device_attribute named
'dev_attr_power'. This can then be added and removed to the device's
directory using:
This declares two structures of type struct device_attribute with respective
names 'dev_attr_type' and 'dev_attr_power'. These two attributes can be
organized as follows into a group:
int device_create_file(struct device *device, struct device_attribute * entry);
void device_remove_file(struct device * dev, struct device_attribute * attr);
static struct attribute *dev_attrs[] = {
&dev_attr_type.attr,
&dev_attr_power.attr,
NULL,
};
Example:
static struct attribute_group dev_attr_group = {
.attrs = dev_attrs,
};
device_create_file(dev,&dev_attr_power);
device_remove_file(dev,&dev_attr_power);
static const struct attribute_group *dev_attr_groups[] = {
&dev_attr_group,
NULL,
};
The file name will be 'power' with a mode of 0644 (-rw-r--r--).
This array of groups can then be associated with a device by setting the
group pointer in struct device before device_register() is invoked:
dev->groups = dev_attr_groups;
device_register(dev);
The device_register() function will use the 'groups' pointer to create the
device attributes and the device_unregister() function will use this pointer
to remove the device attributes.
Word of warning: While the kernel allows device_create_file() and
device_remove_file() to be called on a device at any time, userspace has
@ -84,24 +103,4 @@ not know about the new attributes.
This is important for device driver that need to publish additional
attributes for a device at driver probe time. If the device driver simply
calls device_create_file() on the device structure passed to it, then
userspace will never be notified of the new attributes. Instead, it should
probably use class_create() and class->dev_attrs to set up a list of
desired attributes in the modules_init function, and then in the .probe()
hook, and then use device_create() to create a new device as a child
of the probed device. The new device will generate a new uevent and
properly advertise the new attributes to userspace.
For example, if a driver wanted to add the following attributes:
struct device_attribute mydriver_attribs[] = {
__ATTR(port_count, 0444, port_count_show),
__ATTR(serial_number, 0444, serial_number_show),
NULL
};
Then in the module init function is would do:
mydriver_class = class_create(THIS_MODULE, "my_attrs");
mydriver_class.dev_attr = mydriver_attribs;
And assuming 'dev' is the struct device passed into the probe hook, the driver
probe function would do something like:
device_create(&mydriver_class, dev, chrdev, &private_data, "my_name");
userspace will never be notified of the new attributes.

17
Documentation/feature-removal-schedule.txt
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@ -592,3 +592,20 @@ Why: In 3.0, we can now autodetect internal 3G device and already have
interface that was used by acer-wmi driver. It will replaced by
information log when acer-wmi initial.
Who: Lee, Chun-Yi <jlee@novell.com>
----------------------------
What: The XFS nodelaylog mount option
When: 3.3
Why: The delaylog mode that has been the default since 2.6.39 has proven
stable, and the old code is in the way of additional improvements in
the log code.
Who: Christoph Hellwig <hch@lst.de>
----------------------------
What: iwlagn alias support
When: 3.5
Why: The iwlagn module has been renamed iwlwifi. The alias will be around
for backward compatibility for several cycles and then dropped.
Who: Don Fry <donald.h.fry@intel.com>

2
Documentation/filesystems/9p.txt
View File

@ -92,7 +92,7 @@ OPTIONS
wfdno=n the file descriptor for writing with trans=fd
maxdata=n the number of bytes to use for 9p packet payload (msize)
msize=n the number of bytes to use for 9p packet payload
port=n port to connect to on the remote server

6
Documentation/filesystems/caching/object.txt
View File

@ -127,9 +127,9 @@ fscache_enqueue_object()).
PROVISION OF CPU TIME
---------------------
The work to be done by the various states is given CPU time by the threads of
the slow work facility (see Documentation/slow-work.txt). This is used in
preference to the workqueue facility because:
The work to be done by the various states was given CPU time by the threads of
the slow work facility. This was used in preference to the workqueue facility
because:
(1) Threads may be completely occupied for very long periods of time by a
particular work item. These state actions may be doing sequences of

11
Documentation/filesystems/locks.txt
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@ -53,11 +53,12 @@ fcntl(), with all the problems that implies.
1.3 Mandatory Locking As A Mount Option
---------------------------------------
Mandatory locking, as described in 'Documentation/filesystems/mandatory.txt'
was prior to this release a general configuration option that was valid for
all mounted filesystems. This had a number of inherent dangers, not the
least of which was the ability to freeze an NFS server by asking it to read
a file for which a mandatory lock existed.
Mandatory locking, as described in
'Documentation/filesystems/mandatory-locking.txt' was prior to this release a
general configuration option that was valid for all mounted filesystems. This
had a number of inherent dangers, not the least of which was the ability to
freeze an NFS server by asking it to read a file for which a mandatory lock
existed.
From this release of the kernel, mandatory locking can be turned on and off
on a per-filesystem basis, using the mount options 'mand' and 'nomand'.

2
Documentation/filesystems/nfs/idmapper.txt
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@ -47,7 +47,7 @@ request-key will find the first matching line and corresponding program. In
this case, /some/other/program will handle all uid lookups and
/usr/sbin/nfs.idmap will handle gid, user, and group lookups.
See <file:Documentation/security/keys-request-keys.txt> for more information
See <file:Documentation/security/keys-request-key.txt> for more information
about the request-key function.

5
Documentation/filesystems/pohmelfs/design_notes.txt
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@ -58,8 +58,9 @@ data transfers.
POHMELFS clients operate with a working set of servers and are capable of balancing read-only
operations (like lookups or directory listings) between them according to IO priorities.
Administrators can add or remove servers from the set at run-time via special commands (described
in Documentation/pohmelfs/info.txt file). Writes are replicated to all servers, which are connected
with write permission turned on. IO priority and permissions can be changed in run-time.
in Documentation/filesystems/pohmelfs/info.txt file). Writes are replicated to all servers, which
are connected with write permission turned on. IO priority and permissions can be changed in
run-time.
POHMELFS is capable of full data channel encryption and/or strong crypto hashing.
One can select any kernel supported cipher, encryption mode, hash type and operation mode

2
Documentation/filesystems/proc.txt
View File

@ -1263,7 +1263,7 @@ review the kernel documentation in the directory /usr/src/linux/Documentation.
This chapter is heavily based on the documentation included in the pre 2.2
kernels, and became part of it in version 2.2.1 of the Linux kernel.
Please see: Documentation/sysctls/ directory for descriptions of these
Please see: Documentation/sysctl/ directory for descriptions of these
entries.
------------------------------------------------------------------------------

10
Documentation/filesystems/sysfs.txt
View File

@ -4,7 +4,7 @@ sysfs - _The_ filesystem for exporting kernel objects.
Patrick Mochel <mochel@osdl.org>
Mike Murphy <mamurph@cs.clemson.edu>
Revised: 15 July 2010
Revised: 16 August 2011
Original: 10 January 2003
@ -370,3 +370,11 @@ int driver_create_file(struct device_driver *, const struct driver_attribute *);
void driver_remove_file(struct device_driver *, const struct driver_attribute *);
Documentation
~~~~~~~~~~~~~
The sysfs directory structure and the attributes in each directory define an
ABI between the kernel and user space. As for any ABI, it is important that
this ABI is stable and properly documented. All new sysfs attributes must be
documented in Documentation/ABI. See also Documentation/ABI/README for more
information.

3
Documentation/filesystems/vfs.txt
View File

@ -1053,9 +1053,6 @@ manipulate dentries:
and the dentry is returned. The caller must use dput()
to free the dentry when it finishes using it.
For further information on dentry locking, please refer to the document
Documentation/filesystems/dentry-locking.txt.
Mount Options
=============

6
Documentation/frv/booting.txt
View File

@ -180,9 +180,3 @@ separated by spaces:
This tells the kernel what program to run initially. By default this is
/sbin/init, but /sbin/sash or /bin/sh are common alternatives.
(*) vdc=...
This option configures the MB93493 companion chip visual display
driver. Please see Documentation/frv/mb93493/vdc.txt for more
information.

25
Documentation/hwmon/ad7314 Normal file
View File

@ -0,0 +1,25 @@
Kernel driver ad7314
====================
Supported chips:
* Analog Devices AD7314
Prefix: 'ad7314'
Datasheet: Publicly available at Analog Devices website.
* Analog Devices ADT7301
Prefix: 'adt7301'
Datasheet: Publicly available at Analog Devices website.
* Analog Devices ADT7302
Prefix: 'adt7302'
Datasheet: Publicly available at Analog Devices website.
Description
-----------
Driver supports the above parts. The ad7314 has a 10 bit
sensor with 1lsb = 0.25 degrees centigrade. The adt7301 and
adt7302 have 14 bit sensors with 1lsb = 0.03125 degrees centigrade.
Notes
-----
Currently power down mode is not supported.

40
Documentation/hwmon/adm1275
View File

@ -6,6 +6,10 @@ Supported chips:
Prefix: 'adm1275'
Addresses scanned: -
Datasheet: www.analog.com/static/imported-files/data_sheets/ADM1275.pdf
* Analog Devices ADM1276
Prefix: 'adm1276'
Addresses scanned: -
Datasheet: www.analog.com/static/imported-files/data_sheets/ADM1276.pdf
Author: Guenter Roeck <guenter.roeck@ericsson.com>
@ -13,13 +17,13 @@ Author: Guenter Roeck <guenter.roeck@ericsson.com>
Description
-----------
This driver supports hardware montoring for Analog Devices ADM1275 Hot-Swap
Controller and Digital Power Monitor.
This driver supports hardware montoring for Analog Devices ADM1275 and ADM1276
Hot-Swap Controller and Digital Power Monitor.
The ADM1275 is a hot-swap controller that allows a circuit board to be removed
from or inserted into a live backplane. It also features current and voltage
readback via an integrated 12-bit analog-to-digital converter (ADC), accessed
using a PMBus. interface.
ADM1275 and ADM1276 are hot-swap controllers that allow a circuit board to be
removed from or inserted into a live backplane. They also feature current and
voltage readback via an integrated 12-bit analog-to-digital converter (ADC),
accessed using a PMBus interface.
The driver is a client driver to the core PMBus driver. Please see
Documentation/hwmon/pmbus for details on PMBus client drivers.
@ -48,17 +52,25 @@ attributes are write-only, all other attributes are read-only.
in1_label "vin1" or "vout1" depending on chip variant and
configuration.
in1_input Measured voltage. From READ_VOUT register.
in1_min Minumum Voltage. From VOUT_UV_WARN_LIMIT register.
in1_max Maximum voltage. From VOUT_OV_WARN_LIMIT register.
in1_min_alarm Voltage low alarm. From VOLTAGE_UV_WARNING status.
in1_max_alarm Voltage high alarm. From VOLTAGE_OV_WARNING status.
in1_input Measured voltage.
in1_min Minumum Voltage.
in1_max Maximum voltage.
in1_min_alarm Voltage low alarm.
in1_max_alarm Voltage high alarm.
in1_highest Historical maximum voltage.
in1_reset_history Write any value to reset history.
curr1_label "iout1"
curr1_input Measured current. From READ_IOUT register.
curr1_max Maximum current. From IOUT_OC_WARN_LIMIT register.
curr1_max_alarm Current high alarm. From IOUT_OC_WARN_LIMIT register.
curr1_input Measured current.
curr1_max Maximum current.
curr1_max_alarm Current high alarm.
curr1_lcrit Critical minimum current. Depending on the chip
configuration, either curr1_lcrit or curr1_crit is
supported, but not both.
curr1_lcrit_alarm Critical current low alarm.
curr1_crit Critical maximum current. Depending on the chip
configuration, either curr1_lcrit or curr1_crit is
supported, but not both.
curr1_crit_alarm Critical current high alarm.
curr1_highest Historical maximum current.
curr1_reset_history Write any value to reset history.

14
Documentation/hwmon/coretemp
View File

@ -35,13 +35,6 @@ the Out-Of-Spec bit. Following table summarizes the exported sysfs files:
All Sysfs entries are named with their core_id (represented here by 'X').
tempX_input - Core temperature (in millidegrees Celsius).
tempX_max - All cooling devices should be turned on (on Core2).
Initialized with IA32_THERM_INTERRUPT. When the CPU
temperature reaches this temperature, an interrupt is
generated and tempX_max_alarm is set.
tempX_max_hyst - If the CPU temperature falls below than temperature,
an interrupt is generated and tempX_max_alarm is reset.
tempX_max_alarm - Set if the temperature reaches or exceeds tempX_max.
Reset if the temperature drops to or below tempX_max_hyst.
tempX_crit - Maximum junction temperature (in millidegrees Celsius).
tempX_crit_alarm - Set when Out-of-spec bit is set, never clears.
Correct CPU operation is no longer guaranteed.
@ -49,9 +42,10 @@ tempX_label - Contains string "Core X", where X is processor
number. For Package temp, this will be "Physical id Y",
where Y is the package number.
The TjMax temperature is set to 85 degrees C if undocumented model specific
register (UMSR) 0xee has bit 30 set. If not the TjMax is 100 degrees C as
(sometimes) documented in processor datasheet.
On CPU models which support it, TjMax is read from a model-specific register.
On other models, it is set to an arbitrary value based on weak heuristics.
If these heuristics don't work for you, you can pass the correct TjMax value
as a module parameter (tjmax).
Appendix A. Known TjMax lists (TBD):
Some information comes from ark.intel.com

81
Documentation/hwmon/exynos4_tmu Normal file
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@ -0,0 +1,81 @@
Kernel driver exynos4_tmu
=================
Supported chips:
* ARM SAMSUNG EXYNOS4 series of SoC
Prefix: 'exynos4-tmu'
Datasheet: Not publicly available
Authors: Donggeun Kim <dg77.kim@samsung.com>
Description
-----------
This driver allows to read temperature inside SAMSUNG EXYNOS4 series of SoC.
The chip only exposes the measured 8-bit temperature code value
through a register.
Temperature can be taken from the temperature code.
There are three equations converting from temperature to temperature code.
The three equations are:
1. Two point trimming
Tc = (T - 25) * (TI2 - TI1) / (85 - 25) + TI1
2. One point trimming
Tc = T + TI1 - 25
3. No trimming
Tc = T + 50
Tc: Temperature code, T: Temperature,
TI1: Trimming info for 25 degree Celsius (stored at TRIMINFO register)
Temperature code measured at 25 degree Celsius which is unchanged
TI2: Trimming info for 85 degree Celsius (stored at TRIMINFO register)
Temperature code measured at 85 degree Celsius which is unchanged
TMU(Thermal Management Unit) in EXYNOS4 generates interrupt
when temperature exceeds pre-defined levels.
The maximum number of configurable threshold is four.
The threshold levels are defined as follows:
Level_0: current temperature > trigger_level_0 + threshold
Level_1: current temperature > trigger_level_1 + threshold
Level_2: current temperature > trigger_level_2 + threshold
Level_3: current temperature > trigger_level_3 + threshold
The threshold and each trigger_level are set
through the corresponding registers.
When an interrupt occurs, this driver notify user space of
one of four threshold levels for the interrupt
through kobject_uevent_env and sysfs_notify functions.
Although an interrupt condition for level_0 can be set,
it is not notified to user space through sysfs_notify function.
Sysfs Interface
---------------
name name of the temperature sensor
RO
temp1_input temperature
RO
temp1_max temperature for level_1 interrupt
RO
temp1_crit temperature for level_2 interrupt
RO
temp1_emergency temperature for level_3 interrupt
RO
temp1_max_alarm alarm for level_1 interrupt
RO
temp1_crit_alarm
alarm for level_2 interrupt
RO
temp1_emergency_alarm
alarm for level_3 interrupt
RO

61
Documentation/hwmon/lm75
View File

@ -12,26 +12,46 @@ Supported chips:
Addresses scanned: I2C 0x48 - 0x4f
Datasheet: Publicly available at the National Semiconductor website
http://www.national.com/
* Dallas Semiconductor DS75
Prefix: 'lm75'
Addresses scanned: I2C 0x48 - 0x4f
Datasheet: Publicly available at the Dallas Semiconductor website
http://www.maxim-ic.com/
* Dallas Semiconductor DS1775
Prefix: 'lm75'
Addresses scanned: I2C 0x48 - 0x4f
* Dallas Semiconductor DS75, DS1775
Prefixes: 'ds75', 'ds1775'
Addresses scanned: none
Datasheet: Publicly available at the Dallas Semiconductor website
http://www.maxim-ic.com/
* Maxim MAX6625, MAX6626
Prefix: 'lm75'
Addresses scanned: I2C 0x48 - 0x4b
Prefixes: 'max6625', 'max6626'
Addresses scanned: none
Datasheet: Publicly available at the Maxim website
http://www.maxim-ic.com/
* Microchip (TelCom) TCN75
Prefix: 'lm75'
Addresses scanned: I2C 0x48 - 0x4f
Addresses scanned: none
Datasheet: Publicly available at the Microchip website
http://www.microchip.com/
* Microchip MCP9800, MCP9801, MCP9802, MCP9803
Prefix: 'mcp980x'
Addresses scanned: none
Datasheet: Publicly available at the Microchip website
http://www.microchip.com/
* Analog Devices ADT75
Prefix: 'adt75'
Addresses scanned: none
Datasheet: Publicly available at the Analog Devices website
http://www.analog.com/adt75
* ST Microelectronics STDS75
Prefix: 'stds75'
Addresses scanned: none
Datasheet: Publicly available at the ST website
http://www.st.com/internet/analog/product/121769.jsp
* Texas Instruments TMP100, TMP101, TMP105, TMP75, TMP175, TMP275
Prefixes: 'tmp100', 'tmp101', 'tmp105', 'tmp175', 'tmp75', 'tmp275'
Addresses scanned: none
Datasheet: Publicly available at the Texas Instruments website
http://www.ti.com/product/tmp100
http://www.ti.com/product/tmp101
http://www.ti.com/product/tmp105
http://www.ti.com/product/tmp75
http://www.ti.com/product/tmp175
http://www.ti.com/product/tmp275
Author: Frodo Looijaard <frodol@dds.nl>
@ -50,21 +70,16 @@ range of -55 to +125 degrees.
The LM75 only updates its values each 1.5 seconds; reading it more often
will do no harm, but will return 'old' values.
The LM75 is usually used in combination with LM78-like chips, to measure
the temperature of the processor(s).
The DS75, DS1775, MAX6625, and MAX6626 are supported as well.
They are not distinguished from an LM75. While most of these chips
have three additional bits of accuracy (12 vs. 9 for the LM75),
the additional bits are not supported. Not only that, but these chips will
not be detected if not in 9-bit precision mode (use the force parameter if
needed).
The TCN75 is supported as well, and is not distinguished from an LM75.
The original LM75 was typically used in combination with LM78-like chips
on PC motherboards, to measure the temperature of the processor(s). Clones
are now used in various embedded designs.
The LM75 is essentially an industry standard; there may be other
LM75 clones not listed here, with or without various enhancements,
that are supported.
that are supported. The clones are not detected by the driver, unless
they reproduce the exact register tricks of the original LM75, and must
therefore be instantiated explicitly. The specific enhancements (such as
higher resolution) are not currently supported by the driver.
The LM77 is not supported, contrary to what we pretended for a long time.
Both chips are simply not compatible, value encoding differs.

103
Documentation/hwmon/ltc2978 Normal file
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@ -0,0 +1,103 @@
Kernel driver ltc2978
=====================
Supported chips:
* Linear Technology LTC2978
Prefix: 'ltc2978'
Addresses scanned: -
Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf
* Linear Technology LTC3880
Prefix: 'ltc3880'
Addresses scanned: -
Datasheet: http://cds.linear.com/docs/Datasheet/3880f.pdf
Author: Guenter Roeck <guenter.roeck@ericsson.com>
Description
-----------
The LTC2978 is an octal power supply monitor, supervisor, sequencer and
margin controller. The LTC3880 is a dual, PolyPhase DC/DC synchronous
step-down switching regulator controller.
Usage Notes
-----------
This driver does not probe for PMBus devices. You will have to instantiate
devices explicitly.
Example: the following commands will load the driver for an LTC2978 at address
0x60 on I2C bus #1:
# modprobe ltc2978
# echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
Sysfs attributes
----------------
in1_label "vin"
in1_input Measured input voltage.
in1_min Minimum input voltage.
in1_max Maximum input voltage.
in1_lcrit Critical minimum input voltage.
in1_crit Critical maximum input voltage.
in1_min_alarm Input voltage low alarm.
in1_max_alarm Input voltage high alarm.
in1_lcrit_alarm Input voltage critical low alarm.
in1_crit_alarm Input voltage critical high alarm.
in1_lowest Lowest input voltage. LTC2978 only.
in1_highest Highest input voltage.
in1_reset_history Reset history. Writing into this attribute will reset
history for all attributes.
in[2-9]_label "vout[1-8]". Channels 3 to 9 on LTC2978 only.
in[2-9]_input Measured output voltage.
in[2-9]_min Minimum output voltage.
in[2-9]_max Maximum output voltage.
in[2-9]_lcrit Critical minimum output voltage.
in[2-9]_crit Critical maximum output voltage.
in[2-9]_min_alarm Output voltage low alarm.
in[2-9]_max_alarm Output voltage high alarm.
in[2-9]_lcrit_alarm Output voltage critical low alarm.
in[2-9]_crit_alarm Output voltage critical high alarm.
in[2-9]_lowest Lowest output voltage. LTC2978 only.
in[2-9]_highest Lowest output voltage.
in[2-9]_reset_history Reset history. Writing into this attribute will reset
history for all attributes.
temp[1-3]_input Measured temperature.
On LTC2978, only one temperature measurement is
supported and reflects the internal temperature.
On LTC3880, temp1 and temp2 report external
temperatures, and temp3 reports the internal
temperature.
temp[1-3]_min Mimimum temperature.
temp[1-3]_max Maximum temperature.
temp[1-3]_lcrit Critical low temperature.
temp[1-3]_crit Critical high temperature.
temp[1-3]_min_alarm Chip temperature low alarm.
temp[1-3]_max_alarm Chip temperature high alarm.
temp[1-3]_lcrit_alarm Chip temperature critical low alarm.
temp[1-3]_crit_alarm Chip temperature critical high alarm.
temp[1-3]_lowest Lowest measured temperature. LTC2978 only.
temp[1-3]_highest Highest measured temperature.
temp[1-3]_reset_history Reset history. Writing into this attribute will reset
history for all attributes.
power[1-2]_label "pout[1-2]". LTC3880 only.
power[1-2]_input Measured power.
curr1_label "iin". LTC3880 only.
curr1_input Measured input current.
curr1_max Maximum input current.
curr1_max_alarm Input current high alarm.
curr[2-3]_label "iout[1-2]". LTC3880 only.
curr[2-3]_input Measured input current.
curr[2-3]_max Maximum input current.
curr[2-3]_crit Critical input current.
curr[2-3]_max_alarm Input current high alarm.
curr[2-3]_crit_alarm Input current critical high alarm.

7
Documentation/hwmon/max16065
View File

@ -62,6 +62,13 @@ can be safely used to identify the chip. You will have to instantiate
the devices explicitly. Please see Documentation/i2c/instantiating-devices for
details.
WARNING: Do not access chip registers using the i2cdump command, and do not use
any of the i2ctools commands on a command register (0xa5 to 0xac). The chips
supported by this driver interpret any access to a command register (including
read commands) as request to execute the command in question. This may result in
power loss, board resets, and/or Flash corruption. Worst case, your board may
turn into a brick.
Sysfs entries
-------------

13
Documentation/hwmon/pmbus
View File

@ -8,11 +8,6 @@ Supported chips:
Addresses scanned: -
Datasheet:
http://archive.ericsson.net/service/internet/picov/get?DocNo=28701-EN/LZT146395
* Linear Technology LTC2978
Octal PMBus Power Supply Monitor and Controller
Prefix: 'ltc2978'
Addresses scanned: -
Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf
* ON Semiconductor ADP4000, NCP4200, NCP4208
Prefixes: 'adp4000', 'ncp4200', 'ncp4208'
Addresses scanned: -
@ -20,6 +15,14 @@ Supported chips:
http://www.onsemi.com/pub_link/Collateral/ADP4000-D.PDF
http://www.onsemi.com/pub_link/Collateral/NCP4200-D.PDF
http://www.onsemi.com/pub_link/Collateral/JUNE%202009-%20REV.%200.PDF
* Lineage Power
Prefixes: 'pdt003', 'pdt006', 'pdt012', 'udt020'
Addresses scanned: -
Datasheets:
http://www.lineagepower.com/oem/pdf/PDT003A0X.pdf
http://www.lineagepower.com/oem/pdf/PDT006A0X.pdf
http://www.lineagepower.com/oem/pdf/PDT012A0X.pdf
http://www.lineagepower.com/oem/pdf/UDT020A0X.pdf
* Generic PMBus devices
Prefix: 'pmbus'
Addresses scanned: -

283
Documentation/hwmon/pmbus-core Normal file
View File

@ -0,0 +1,283 @@
PMBus core driver and internal API
==================================
Introduction
============
[from pmbus.org] The Power Management Bus (PMBus) is an open standard
power-management protocol with a fully defined command language that facilitates
communication with power converters and other devices in a power system. The
protocol is implemented over the industry-standard SMBus serial interface and
enables programming, control, and real-time monitoring of compliant power
conversion products. This flexible and highly versatile standard allows for
communication between devices based on both analog and digital technologies, and
provides true interoperability which will reduce design complexity and shorten
time to market for power system designers. Pioneered by leading power supply and
semiconductor companies, this open power system standard is maintained and
promoted by the PMBus Implementers Forum (PMBus-IF), comprising 30+ adopters
with the objective to provide support to, and facilitate adoption among, users.
Unfortunately, while PMBus commands are standardized, there are no mandatory
commands, and manufacturers can add as many non-standard commands as they like.
Also, different PMBUs devices act differently if non-supported commands are
executed. Some devices return an error, some devices return 0xff or 0xffff and
set a status error flag, and some devices may simply hang up.
Despite all those difficulties, a generic PMBus device driver is still useful
and supported since kernel version 2.6.39. However, it was necessary to support
device specific extensions in addition to the core PMBus driver, since it is
simply unknown what new device specific functionality PMBus device developers
come up with next.
To make device specific extensions as scalable as possible, and to avoid having
to modify the core PMBus driver repeatedly for new devices, the PMBus driver was
split into core, generic, and device specific code. The core code (in
pmbus_core.c) provides generic functionality. The generic code (in pmbus.c)
provides support for generic PMBus devices. Device specific code is responsible
for device specific initialization and, if needed, maps device specific
functionality into generic functionality. This is to some degree comparable
to PCI code, where generic code is augmented as needed with quirks for all kinds
of devices.
PMBus device capabilities auto-detection
========================================
For generic PMBus devices, code in pmbus.c attempts to auto-detect all supported
PMBus commands. Auto-detection is somewhat limited, since there are simply too
many variables to consider. For example, it is almost impossible to autodetect
which PMBus commands are paged and which commands are replicated across all
pages (see the PMBus specification for details on multi-page PMBus devices).
For this reason, it often makes sense to provide a device specific driver if not
all commands can be auto-detected. The data structures in this driver can be
used to inform the core driver about functionality supported by individual
chips.
Some commands are always auto-detected. This applies to all limit commands
(lcrit, min, max, and crit attributes) as well as associated alarm attributes.
Limits and alarm attributes are auto-detected because there are simply too many
possible combinations to provide a manual configuration interface.
PMBus internal API
==================
The API between core and device specific PMBus code is defined in
drivers/hwmon/pmbus/pmbus.h. In addition to the internal API, pmbus.h defines
standard PMBus commands and virtual PMBus commands.
Standard PMBus commands
-----------------------
Standard PMBus commands (commands values 0x00 to 0xff) are defined in the PMBUs
specification.
Virtual PMBus commands
----------------------
Virtual PMBus commands are provided to enable support for non-standard
functionality which has been implemented by several chip vendors and is thus
desirable to support.
Virtual PMBus commands start with command value 0x100 and can thus easily be
distinguished from standard PMBus commands (which can not have values larger
than 0xff). Support for virtual PMBus commands is device specific and thus has
to be implemented in device specific code.
Virtual commands are named PMBUS_VIRT_xxx and start with PMBUS_VIRT_BASE. All
virtual commands are word sized.
There are currently two types of virtual commands.
- READ commands are read-only; writes are either ignored or return an error.
- RESET commands are read/write. Reading reset registers returns zero
(used for detection), writing any value causes the associated history to be
reset.
Virtual commands have to be handled in device specific driver code. Chip driver
code returns non-negative values if a virtual command is supported, or a
negative error code if not. The chip driver may return -ENODATA or any other
Linux error code in this case, though an error code other than -ENODATA is
handled more efficiently and thus preferred. Either case, the calling PMBus
core code will abort if the chip driver returns an error code when reading
or writing virtual registers (in other words, the PMBus core code will never
send a virtual command to a chip).
PMBus driver information
------------------------
PMBus driver information, defined in struct pmbus_driver_info, is the main means
for device specific drivers to pass information to the core PMBus driver.
Specifically, it provides the following information.
- For devices supporting its data in Direct Data Format, it provides coefficients
for converting register values into normalized data. This data is usually
provided by chip manufacturers in device datasheets.
- Supported chip functionality can be provided to the core driver. This may be
necessary for chips which react badly if non-supported commands are executed,
and/or to speed up device detection and initialization.
- Several function entry points are provided to support overriding and/or
augmenting generic command execution. This functionality can be used to map
non-standard PMBus commands to standard commands, or to augment standard
command return values with device specific information.
API functions
-------------
Functions provided by chip driver
---------------------------------
All functions return the command return value (read) or zero (write) if
successful. A return value of -ENODATA indicates that there is no manufacturer
specific command, but that a standard PMBus command may exist. Any other
negative return value indicates that the commands does not exist for this
chip, and that no attempt should be made to read or write the standard
command.
As mentioned above, an exception to this rule applies to virtual commands,
which _must_ be handled in driver specific code. See "Virtual PMBus Commands"
above for more details.
Command execution in the core PMBus driver code is as follows.
if (chip_access_function) {
status = chip_access_function();
if (status != -ENODATA)
return status;
}
if (command >= PMBUS_VIRT_BASE) /* For word commands/registers only */
return -EINVAL;
return generic_access();
Chip drivers may provide pointers to the following functions in struct
pmbus_driver_info. All functions are optional.
int (*read_byte_data)(struct i2c_client *client, int page, int reg);
Read byte from page <page>, register <reg>.
<page> may be -1, which means "current page".
int (*read_word_data)(struct i2c_client *client, int page, int reg);
Read word from page <page>, register <reg>.
int (*write_word_data)(struct i2c_client *client, int page, int reg,
u16 word);
Write word to page <page>, register <reg>.
int (*write_byte)(struct i2c_client *client, int page, u8 value);
Write byte to page <page>, register <reg>.
<page> may be -1, which means "current page".
int (*identify)(struct i2c_client *client, struct pmbus_driver_info *info);
Determine supported PMBus functionality. This function is only necessary
if a chip driver supports multiple chips, and the chip functionality is not
pre-determined. It is currently only used by the generic pmbus driver
(pmbus.c).
Functions exported by core driver
---------------------------------
Chip drivers are expected to use the following functions to read or write
PMBus registers. Chip drivers may also use direct I2C commands. If direct I2C
commands are used, the chip driver code must not directly modify the current
page, since the selected page is cached in the core driver and the core driver
will assume that it is selected. Using pmbus_set_page() to select a new page
is mandatory.
int pmbus_set_page(struct i2c_client *client, u8 page);
Set PMBus page register to <page> for subsequent commands.
int pmbus_read_word_data(struct i2c_client *client, u8 page, u8 reg);
Read word data from <page>, <reg>. Similar to i2c_smbus_read_word_data(), but
selects page first.
int pmbus_write_word_data(struct i2c_client *client, u8 page, u8 reg,
u16 word);
Write word data to <page>, <reg>. Similar to i2c_smbus_write_word_data(), but
selects page first.
int pmbus_read_byte_data(struct i2c_client *client, int page, u8 reg);
Read byte data from <page>, <reg>. Similar to i2c_smbus_read_byte_data(), but
selects page first. <page> may be -1, which means "current page".
int pmbus_write_byte(struct i2c_client *client, int page, u8 value);
Write byte data to <page>, <reg>. Similar to i2c_smbus_write_byte(), but
selects page first. <page> may be -1, which means "current page".
void pmbus_clear_faults(struct i2c_client *client);
Execute PMBus "Clear Fault" command on all chip pages.
This function calls the device specific write_byte function if defined.
Therefore, it must _not_ be called from that function.
bool pmbus_check_byte_register(struct i2c_client *client, int page, int reg);
Check if byte register exists. Return true if the register exists, false
otherwise.
This function calls the device specific write_byte function if defined to
obtain the chip status. Therefore, it must _not_ be called from that function.
bool pmbus_check_word_register(struct i2c_client *client, int page, int reg);
Check if word register exists. Return true if the register exists, false
otherwise.
This function calls the device specific write_byte function if defined to
obtain the chip status. Therefore, it must _not_ be called from that function.
int pmbus_do_probe(struct i2c_client *client, const struct i2c_device_id *id,
struct pmbus_driver_info *info);
Execute probe function. Similar to standard probe function for other drivers,
with the pointer to struct pmbus_driver_info as additional argument. Calls
identify function if supported. Must only be called from device probe
function.
void pmbus_do_remove(struct i2c_client *client);
Execute driver remove function. Similar to standard driver remove function.
const struct pmbus_driver_info
*pmbus_get_driver_info(struct i2c_client *client);
Return pointer to struct pmbus_driver_info as passed to pmbus_do_probe().
PMBus driver platform data
==========================
PMBus platform data is defined in include/linux/i2c/pmbus.h. Platform data
currently only provides a flag field with a single bit used.
#define PMBUS_SKIP_STATUS_CHECK (1 << 0)
struct pmbus_platform_data {
u32 flags; /* Device specific flags */
};
Flags
-----
PMBUS_SKIP_STATUS_CHECK
During register detection, skip checking the status register for
communication or command errors.
Some PMBus chips respond with valid data when trying to read an unsupported
register. For such chips, checking the status register is mandatory when
trying to determine if a chip register exists or not.
Other PMBus chips don't support the STATUS_CML register, or report
communication errors for no explicable reason. For such chips, checking the
status register must be disabled.
Some i2c controllers do not support single-byte commands (write commands with
no data, i2c_smbus_write_byte()). With such controllers, clearing the status
register is impossible, and the PMBUS_SKIP_STATUS_CHECK flag must be set.

125
Documentation/hwmon/zl6100 Normal file
View File

@ -0,0 +1,125 @@
Kernel driver zl6100
====================
Supported chips:
* Intersil / Zilker Labs ZL2004
Prefix: 'zl2004'
Addresses scanned: -
Datasheet: http://www.intersil.com/data/fn/fn6847.pdf
* Intersil / Zilker Labs ZL2006
Prefix: 'zl2006'
Addresses scanned: -
Datasheet: http://www.intersil.com/data/fn/fn6850.pdf
* Intersil / Zilker Labs ZL2008
Prefix: 'zl2008'
Addresses scanned: -
Datasheet: http://www.intersil.com/data/fn/fn6859.pdf
* Intersil / Zilker Labs ZL2105
Prefix: 'zl2105'
Addresses scanned: -
Datasheet: http://www.intersil.com/data/fn/fn6851.pdf
* Intersil / Zilker Labs ZL2106
Prefix: 'zl2106'
Addresses scanned: -
Datasheet: http://www.intersil.com/data/fn/fn6852.pdf
* Intersil / Zilker Labs ZL6100
Prefix: 'zl6100'
Addresses scanned: -
Datasheet: http://www.intersil.com/data/fn/fn6876.pdf
* Intersil / Zilker Labs ZL6105
Prefix: 'zl6105'
Addresses scanned: -
Datasheet: http://www.intersil.com/data/fn/fn6906.pdf
Author: Guenter Roeck <guenter.roeck@ericsson.com>
Description
-----------
This driver supports hardware montoring for Intersil / Zilker Labs ZL6100 and
compatible digital DC-DC controllers.
The driver is a client driver to the core PMBus driver. Please see
Documentation/hwmon/pmbus and Documentation.hwmon/pmbus-core for details
on PMBus client drivers.
Usage Notes
-----------
This driver does not auto-detect devices. You will have to instantiate the
devices explicitly. Please see Documentation/i2c/instantiating-devices for
details.
WARNING: Do not access chip registers using the i2cdump command, and do not use
any of the i2ctools commands on a command register used to save and restore
configuration data (0x11, 0x12, 0x15, 0x16, and 0xf4). The chips supported by
this driver interpret any access to those command registers (including read
commands) as request to execute the command in question. Unless write accesses
to those registers are protected, this may result in power loss, board resets,
and/or Flash corruption. Worst case, your board may turn into a brick.
Platform data support
---------------------
The driver supports standard PMBus driver platform data.
Module parameters
-----------------
delay
-----
Some Intersil/Zilker Labs DC-DC controllers require a minimum interval between
I2C bus accesses. According to Intersil, the minimum interval is 2 ms, though
1 ms appears to be sufficient and has not caused any problems in testing.
The problem is known to affect ZL6100, ZL2105, and ZL2008. It is known not to
affect ZL2004 and ZL6105. The driver automatically sets the interval to 1 ms
except for ZL2004 and ZL6105. To enable manual override, the driver provides a
writeable module parameter, 'delay', which can be used to set the interval to
a value between 0 and 65,535 microseconds.
Sysfs entries
-------------
The following attributes are supported. Limits are read-write; all other
attributes are read-only.
in1_label "vin"
in1_input Measured input voltage.
in1_min Minimum input voltage.
in1_max Maximum input voltage.
in1_lcrit Critical minumum input voltage.
in1_crit Critical maximum input voltage.
in1_min_alarm Input voltage low alarm.
in1_max_alarm Input voltage high alarm.
in1_lcrit_alarm Input voltage critical low alarm.
in1_crit_alarm Input voltage critical high alarm.
in2_label "vout1"
in2_input Measured output voltage.
in2_lcrit Critical minumum output Voltage.
in2_crit Critical maximum output voltage.
in2_lcrit_alarm Critical output voltage critical low alarm.
in2_crit_alarm Critical output voltage critical high alarm.
curr1_label "iout1"
curr1_input Measured output current.
curr1_lcrit Critical minimum output current.
curr1_crit Critical maximum output current.
curr1_lcrit_alarm Output current critical low alarm.
curr1_crit_alarm Output current critical high alarm.
temp[12]_input Measured temperature.
temp[12]_min Minimum temperature.
temp[12]_max Maximum temperature.
temp[12]_lcrit Critical low temperature.
temp[12]_crit Critical high temperature.
temp[12]_min_alarm Chip temperature low alarm.
temp[12]_max_alarm Chip temperature high alarm.
temp[12]_lcrit_alarm Chip temperature critical low alarm.
temp[12]_crit_alarm Chip temperature critical high alarm.

295
Documentation/input/elantech.txt
View File

@ -16,15 +16,28 @@ Contents
1. Introduction
2. Extra knobs
3. Hardware version 1
3.1 Registers
3.2 Native relative mode 4 byte packet format
3.3 Native absolute mode 4 byte packet format
4. Hardware version 2
3. Differentiating hardware versions
4. Hardware version 1
4.1 Registers
4.2 Native absolute mode 6 byte packet format
4.2.1 One finger touch
4.2.2 Two finger touch
4.2 Native relative mode 4 byte packet format
4.3 Native absolute mode 4 byte packet format
5. Hardware version 2
5.1 Registers
5.2 Native absolute mode 6 byte packet format
5.2.1 Parity checking and packet re-synchronization
5.2.2 One/Three finger touch
5.2.3 Two finger touch
6. Hardware version 3
6.1 Registers
6.2 Native absolute mode 6 byte packet format
6.2.1 One/Three finger touch
6.2.2 Two finger touch
7. Hardware version 4
7.1 Registers
7.2 Native absolute mode 6 byte packet format
7.2.1 Status packet
7.2.2 Head packet
7.2.3 Motion packet
@ -375,7 +388,7 @@ For all the other ones, there are just a few constant bits:
In case an error is detected, all the packets are shifted by one (and packet[0] is discarded).
5.2.1 One/Three finger touch
5.2.2 One/Three finger touch
~~~~~~~~~~~~~~~~
byte 0:
@ -384,19 +397,19 @@ byte 0:
n1 n0 w3 w2 . . R L
L, R = 1 when Left, Right mouse button pressed
n1..n0 = numbers of fingers on touchpad
n1..n0 = number of fingers on touchpad
byte 1:
bit 7 6 5 4 3 2 1 0
p7 p6 p5 p4 . x10 x9 x8
p7 p6 p5 p4 x11 x10 x9 x8
byte 2:
bit 7 6 5 4 3 2 1 0
x7 x6 x5 x4 x3 x2 x1 x0
x10..x0 = absolute x value (horizontal)
x11..x0 = absolute x value (horizontal)
byte 3:
@ -420,7 +433,7 @@ byte 3:
byte 4:
bit 7 6 5 4 3 2 1 0
p3 p1 p2 p0 . . y9 y8
p3 p1 p2 p0 y11 y10 y9 y8
p7..p0 = pressure (not EF113)
@ -429,10 +442,10 @@ byte 5:
bit 7 6 5 4 3 2 1 0
y7 y6 y5 y4 y3 y2 y1 y0
y9..y0 = absolute y value (vertical)
y11..y0 = absolute y value (vertical)
4.2.2 Two finger touch
5.2.3 Two finger touch
~~~~~~~~~~~~~~~~
Note that the two pairs of coordinates are not exactly the coordinates of the
@ -446,7 +459,7 @@ byte 0:
n1 n0 ay8 ax8 . . R L
L, R = 1 when Left, Right mouse button pressed
n1..n0 = numbers of fingers on touchpad
n1..n0 = number of fingers on touchpad
byte 1:
@ -480,3 +493,253 @@ byte 5:
by7 by8 by5 by4 by3 by2 by1 by0
by8..by0 = upper-right finger absolute y value
/////////////////////////////////////////////////////////////////////////////
6. Hardware version 3
==================
6.1 Registers
~~~~~~~~~
* reg_10
bit 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 A
A: 1 = enable absolute tracking
6.2 Native absolute mode 6 byte packet format
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 and 3 finger touch shares the same 6-byte packet format, except that
3 finger touch only reports the position of the center of all three fingers.
Firmware would send 12 bytes of data for 2 finger touch.
Note on debounce:
In case the box has unstable power supply or other electricity issues, or
when number of finger changes, F/W would send "debounce packet" to inform
driver that the hardware is in debounce status.
The debouce packet has the following signature:
byte 0: 0xc4
byte 1: 0xff
byte 2: 0xff
byte 3: 0x02
byte 4: 0xff
byte 5: 0xff
When we encounter this kind of packet, we just ignore it.
6.2.1 One/Three finger touch
~~~~~~~~~~~~~~~~~~~~~~
byte 0:
bit 7 6 5 4 3 2 1 0
n1 n0 w3 w2 0 1 R L
L, R = 1 when Left, Right mouse button pressed
n1..n0 = number of fingers on touchpad
byte 1:
bit 7 6 5 4 3 2 1 0
p7 p6 p5 p4 x11 x10 x9 x8
byte 2:
bit 7 6 5 4 3 2 1 0
x7 x6 x5 x4 x3 x2 x1 x0
x11..x0 = absolute x value (horizontal)
byte 3:
bit 7 6 5 4 3 2 1 0
0 0 w1 w0 0 0 1 0
w3..w0 = width of the finger touch
byte 4:
bit 7 6 5 4 3 2 1 0
p3 p1 p2 p0 y11 y10 y9 y8
p7..p0 = pressure
byte 5:
bit 7 6 5 4 3 2 1 0
y7 y6 y5 y4 y3 y2 y1 y0
y11..y0 = absolute y value (vertical)
6.2.2 Two finger touch
~~~~~~~~~~~~~~~~
The packet format is exactly the same for two finger touch, except the hardware
sends two 6 byte packets. The first packet contains data for the first finger,
the second packet has data for the second finger. So for two finger touch a
total of 12 bytes are sent.
/////////////////////////////////////////////////////////////////////////////
7. Hardware version 4
==================
7.1 Registers
~~~~~~~~~
* reg_07
bit 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 A
A: 1 = enable absolute tracking
7.2 Native absolute mode 6 byte packet format
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
v4 hardware is a true multitouch touchpad, capable of tracking up to 5 fingers.
Unfortunately, due to PS/2's limited bandwidth, its packet format is rather
complex.
Whenever the numbers or identities of the fingers changes, the hardware sends a
status packet to indicate how many and which fingers is on touchpad, followed by
head packets or motion packets. A head packet contains data of finger id, finger
position (absolute x, y values), width, and pressure. A motion packet contains
two fingers' position delta.
For example, when status packet tells there are 2 fingers on touchpad, then we
can expect two following head packets. If the finger status doesn't change,
the following packets would be motion packets, only sending delta of finger
position, until we receive a status packet.
One exception is one finger touch. when a status packet tells us there is only
one finger, the hardware would just send head packets afterwards.
7.2.1 Status packet
~~~~~~~~~~~~~
byte 0:
bit 7 6 5 4 3 2 1 0
. . . . 0 1 R L
L, R = 1 when Left, Right mouse button pressed
byte 1:
bit 7 6 5 4 3 2 1 0
. . . ft4 ft3 ft2 ft1 ft0
ft4 ft3 ft2 ft1 ft0 ftn = 1 when finger n is on touchpad
byte 2: not used
byte 3:
bit 7 6 5 4 3 2 1 0
. . . 1 0 0 0 0
constant bits
byte 4:
bit 7 6 5 4 3 2 1 0
p . . . . . . .
p = 1 for palm
byte 5: not used
7.2.2 Head packet
~~~~~~~~~~~
byte 0:
bit 7 6 5 4 3 2 1 0
w3 w2 w1 w0 0 1 R L
L, R = 1 when Left, Right mouse button pressed
w3..w0 = finger width (spans how many trace lines)
byte 1:
bit 7 6 5 4 3 2 1 0
p7 p6 p5 p4 x11 x10 x9 x8
byte 2:
bit 7 6 5 4 3 2 1 0
x7 x6 x5 x4 x3 x2 x1 x0
x11..x0 = absolute x value (horizontal)
byte 3:
bit 7 6 5 4 3 2 1 0
id2 id1 id0 1 0 0 0 1
id2..id0 = finger id
byte 4:
bit 7 6 5 4 3 2 1 0
p3 p1 p2 p0 y11 y10 y9 y8
p7..p0 = pressure
byte 5:
bit 7 6 5 4 3 2 1 0
y7 y6 y5 y4 y3 y2 y1 y0
y11..y0 = absolute y value (vertical)
7.2.3 Motion packet
~~~~~~~~~~~~~
byte 0:
bit 7 6 5 4 3 2 1 0
id2 id1 id0 w 0 1 R L
L, R = 1 when Left, Right mouse button pressed
id2..id0 = finger id
w = 1 when delta overflows (> 127 or < -128), in this case
firmware sends us (delta x / 5) and (delta y / 5)
byte 1:
bit 7 6 5 4 3 2 1 0
x7 x6 x5 x4 x3 x2 x1 x0
x7..x0 = delta x (two's complement)
byte 2:
bit 7 6 5 4 3 2 1 0
y7 y6 y5 y4 y3 y2 y1 y0
y7..y0 = delta y (two's complement)
byte 3:
bit 7 6 5 4 3 2 1 0
id2 id1 id0 1 0 0 1 0
id2..id0 = finger id
byte 4:
bit 7 6 5 4 3 2 1 0
x7 x6 x5 x4 x3 x2 x1 x0
x7..x0 = delta x (two's complement)
byte 5:
bit 7 6 5 4 3 2 1 0
y7 y6 y5 y4 y3 y2 y1 y0
y7..y0 = delta y (two's complement)
byte 0 ~ 2 for one finger
byte 3 ~ 5 for another

2
Documentation/input/input.txt
View File

@ -111,7 +111,7 @@ LCDs and many other purposes.
The monitor and speaker controls should be easy to add to the hid/input
interface, but for the UPSs and LCDs it doesn't make much sense. For this,
the hiddev interface was designed. See Documentation/usb/hiddev.txt
the hiddev interface was designed. See Documentation/hid/hiddev.txt
for more information about it.
The usage of the usbhid module is very simple, it takes no parameters,

14
Documentation/input/multi-touch-protocol.txt
View File

@ -65,6 +65,20 @@ the full state of each initiated contact has to reside in the receiving
end. Upon receiving an MT event, one simply updates the appropriate
attribute of the current slot.
Some devices identify and/or track more contacts than they can report to the
driver. A driver for such a device should associate one type B slot with each
contact that is reported by the hardware. Whenever the identity of the
contact associated with a slot changes, the driver should invalidate that
slot by changing its ABS_MT_TRACKING_ID. If the hardware signals that it is
tracking more contacts than it is currently reporting, the driver should use
a BTN_TOOL_*TAP event to inform userspace of the total number of contacts
being tracked by the hardware at that moment. The driver should do this by
explicitly sending the corresponding BTN_TOOL_*TAP event and setting
use_count to false when calling input_mt_report_pointer_emulation().
The driver should only advertise as many slots as the hardware can report.
Userspace can detect that a driver can report more total contacts than slots
by noting that the largest supported BTN_TOOL_*TAP event is larger than the
total number of type B slots reported in the absinfo for the ABS_MT_SLOT axis.
Protocol Example A
------------------

2
Documentation/ioctl/ioctl-number.txt
View File

@ -319,4 +319,6 @@ Code Seq#(hex) Include File Comments
<mailto:thomas@winischhofer.net>
0xF4 00-1F video/mbxfb.h mbxfb
<mailto:raph@8d.com>
0xF6 all LTTng Linux Trace Toolkit Next Generation
<mailto:mathieu.desnoyers@efficios.com>
0xFD all linux/dm-ioctl.h

4
Documentation/kernel-docs.txt
View File

@ -300,7 +300,7 @@
* Title: "The Kernel Hacking HOWTO"
Author: Various Talented People, and Rusty.
Location: in kernel tree, Documentation/DocBook/kernel-hacking/
Location: in kernel tree, Documentation/DocBook/kernel-hacking.tmpl
(must be built as "make {htmldocs | psdocs | pdfdocs})
Keywords: HOWTO, kernel contexts, deadlock, locking, modules,
symbols, return conventions.
@ -351,7 +351,7 @@
* Title: "Linux Kernel Locking HOWTO"
Author: Various Talented People, and Rusty.
Location: in kernel tree, Documentation/DocBook/kernel-locking/
Location: in kernel tree, Documentation/DocBook/kernel-locking.tmpl
(must be built as "make {htmldocs | psdocs | pdfdocs})
Keywords: locks, locking, spinlock, semaphore, atomic, race
condition, bottom halves, tasklets, softirqs.

44
Documentation/kernel-parameters.txt
View File

@ -49,6 +49,7 @@ parameter is applicable:
EDD BIOS Enhanced Disk Drive Services (EDD) is enabled
EFI EFI Partitioning (GPT) is enabled
EIDE EIDE/ATAPI support is enabled.
EVM Extended Verification Module
FB The frame buffer device is enabled.
FTRACE Function tracing enabled.
GCOV GCOV profiling is enabled.
@ -163,7 +164,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
rsdt -- prefer RSDT over (default) XSDT
copy_dsdt -- copy DSDT to memory
See also Documentation/power/pm.txt, pci=noacpi
See also Documentation/power/runtime_pm.txt, pci=noacpi
acpi_rsdp= [ACPI,EFI,KEXEC]
Pass the RSDP address to the kernel, mostly used
@ -319,7 +320,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
amijoy.map= [HW,JOY] Amiga joystick support
Map of devices attached to JOY0DAT and JOY1DAT
Format: <a>,<b>
See also Documentation/kernel/input/joystick.txt
See also Documentation/input/joystick.txt
analog.map= [HW,JOY] Analog joystick and gamepad support
Specifies type or capabilities of an analog joystick
@ -408,7 +409,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
bttv.radio= Most important insmod options are available as
kernel args too.
bttv.pll= See Documentation/video4linux/bttv/Insmod-options
bttv.tuner= and Documentation/video4linux/bttv/CARDLIST
bttv.tuner=
bulk_remove=off [PPC] This parameter disables the use of the pSeries
firmware feature for flushing multiple hpte entries
@ -724,7 +725,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
elevator= [IOSCHED]
Format: {"cfq" | "deadline" | "noop"}
See Documentation/block/as-iosched.txt and
See Documentation/block/cfq-iosched.txt and
Documentation/block/deadline-iosched.txt for details.
elfcorehdr= [IA-64,PPC,SH,X86]
@ -760,12 +761,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
This option is obsoleted by the "netdev=" option, which
has equivalent usage. See its documentation for details.
evm= [EVM]
Format: { "fix" }
Permit 'security.evm' to be updated regardless of
current integrity status.
failslab=
fail_page_alloc=
fail_make_request=[KNL]
General fault injection mechanism.
Format: <interval>,<probability>,<space>,<times>
See also /Documentation/fault-injection/.
See also Documentation/fault-injection/.
floppy= [HW]
See Documentation/blockdev/floppy.txt.
@ -1014,10 +1020,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
has the capability. With this option, super page will
not be supported.
intremap= [X86-64, Intel-IOMMU]
Format: { on (default) | off | nosid }
on enable Interrupt Remapping (default)
off disable Interrupt Remapping
nosid disable Source ID checking
no_x2apic_optout
BIOS x2APIC opt-out request will be ignored
inttest= [IA-64]
@ -2086,9 +2093,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Override pmtimer IOPort with a hex value.
e.g. pmtmr=0x508
pnp.debug [PNP]
Enable PNP debug messages. This depends on the
CONFIG_PNP_DEBUG_MESSAGES option.
pnp.debug=1 [PNP]
Enable PNP debug messages (depends on the
CONFIG_PNP_DEBUG_MESSAGES option). Change at run-time
via /sys/module/pnp/parameters/debug. We always show
current resource usage; turning this on also shows
possible settings and some assignment information.
pnpacpi= [ACPI]
{ off }
@ -2237,6 +2247,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
in <PAGE_SIZE> units (needed only for swap files).
See Documentation/power/swsusp-and-swap-files.txt
resumedelay= [HIBERNATION] Delay (in seconds) to pause before attempting to
read the resume files
resumewait [HIBERNATION] Wait (indefinitely) for resume device to show up.
Useful for devices that are detected asynchronously
(e.g. USB and MMC devices).
hibernate= [HIBERNATION]
noresume Don't check if there's a hibernation image
present during boot.
@ -2372,7 +2389,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Format: <integer>
sonypi.*= [HW] Sony Programmable I/O Control Device driver
See Documentation/sonypi.txt
See Documentation/laptops/sonypi.txt
specialix= [HW,SERIAL] Specialix multi-serial port adapter
See Documentation/serial/specialix.txt.
@ -2703,10 +2720,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
functions are at fixed addresses, they make nice
targets for exploits that can control RIP.
emulate [default] Vsyscalls turn into traps and are
emulated reasonably safely.
emulate Vsyscalls turn into traps and are emulated
reasonably safely.
native Vsyscalls are native syscall instructions.
native [default] Vsyscalls are native syscall
instructions.
This is a little bit faster than trapping
and makes a few dynamic recompilers work
better than they would in emulation mode.

4
Documentation/laptops/thinkpad-acpi.txt
View File

@ -736,7 +736,7 @@ status as "unknown". The available commands are:
sysfs notes:
The ThinkLight sysfs interface is documented by the LED class
documentation, in Documentation/leds-class.txt. The ThinkLight LED name
documentation, in Documentation/leds/leds-class.txt. The ThinkLight LED name
is "tpacpi::thinklight".
Due to limitations in the sysfs LED class, if the status of the ThinkLight
@ -833,7 +833,7 @@ All of the above can be turned on and off and can be made to blink.
sysfs notes:
The ThinkPad LED sysfs interface is described in detail by the LED class
documentation, in Documentation/leds-class.txt.
documentation, in Documentation/leds/leds-class.txt.
The LEDs are named (in LED ID order, from 0 to 12):
"tpacpi::power", "tpacpi:orange:batt", "tpacpi:green:batt",

4
Documentation/media-framework.txt
View File

@ -9,8 +9,8 @@ Introduction
------------
The media controller API is documented in DocBook format in
Documentation/DocBook/v4l/media-controller.xml. This document will focus on
the kernel-side implementation of the media framework.
Documentation/DocBook/media/v4l/media-controller.xml. This document will focus
on the kernel-side implementation of the media framework.
Abstract media device model

2
Documentation/memory-barriers.txt
View File

@ -438,7 +438,7 @@ There are certain things that the Linux kernel memory barriers do not guarantee:
[*] For information on bus mastering DMA and coherency please read:
Documentation/PCI/pci.txt
Documentation/PCI/PCI-DMA-mapping.txt
Documentation/DMA-API-HOWTO.txt
Documentation/DMA-API.txt

8
Documentation/networking/batman-adv.txt
View File

@ -1,4 +1,4 @@
[state: 17-04-2011]
[state: 21-08-2011]
BATMAN-ADV
----------
@ -68,9 +68,9 @@ All mesh wide settings can be found in batman's own interface
folder:
# ls /sys/class/net/bat0/mesh/
# aggregated_ogms gw_bandwidth hop_penalty
# bonding gw_mode orig_interval
# fragmentation gw_sel_class vis_mode
# aggregated_ogms fragmentation gw_sel_class vis_mode
# ap_isolation gw_bandwidth hop_penalty
# bonding gw_mode orig_interval
There is a special folder for debugging information:

3
Documentation/networking/dmfe.txt
View File

@ -1,3 +1,5 @@
Note: This driver doesn't have a maintainer.
Davicom DM9102(A)/DM9132/DM9801 fast ethernet driver for Linux.
This program is free software; you can redistribute it and/or
@ -55,7 +57,6 @@ Test and make sure PCI latency is now correct for all cases.
Authors:
Sten Wang <sten_wang@davicom.com.tw > : Original Author
Tobias Ringstrom <tori@unhappy.mine.nu> : Current Maintainer
Contributors:

21
Documentation/networking/ip-sysctl.txt
View File

@ -1042,9 +1042,14 @@ conf/interface/*:
The functional behaviour for certain settings is different
depending on whether local forwarding is enabled or not.
accept_ra - BOOLEAN
accept_ra - INTEGER
Accept Router Advertisements; autoconfigure using them.
It also determines whether or not to transmit Router
Solicitations. If and only if the functional setting is to
accept Router Advertisements, Router Solicitations will be
transmitted.
Possible values are:
0 Do not accept Router Advertisements.
1 Accept Router Advertisements if forwarding is disabled.
@ -1106,7 +1111,7 @@ dad_transmits - INTEGER
The amount of Duplicate Address Detection probes to send.
Default: 1
forwarding - BOOLEAN
forwarding - INTEGER
Configure interface-specific Host/Router behaviour.
Note: It is recommended to have the same setting on all
@ -1115,14 +1120,14 @@ forwarding - BOOLEAN
Possible values are:
0 Forwarding disabled
1 Forwarding enabled
2 Forwarding enabled (Hybrid Mode)
FALSE (0):
By default, Host behaviour is assumed. This means:
1. IsRouter flag is not set in Neighbour Advertisements.
2. Router Solicitations are being sent when necessary.
2. If accept_ra is TRUE (default), transmit Router
Solicitations.
3. If accept_ra is TRUE (default), accept Router
Advertisements (and do autoconfiguration).
4. If accept_redirects is TRUE (default), accept Redirects.
@ -1133,16 +1138,10 @@ forwarding - BOOLEAN
This means exactly the reverse from the above:
1. IsRouter flag is set in Neighbour Advertisements.
2. Router Solicitations are not sent.
2. Router Solicitations are not sent unless accept_ra is 2.
3. Router Advertisements are ignored unless accept_ra is 2.
4. Redirects are ignored.
TRUE (2):
Hybrid mode. Same behaviour as TRUE, except for:
2. Router Solicitations are being sent when necessary.
Default: 0 (disabled) if global forwarding is disabled (default),
otherwise 1 (enabled).

4
Documentation/networking/mac80211-injection.txt
View File

@ -23,6 +23,10 @@ radiotap headers and used to control injection:
IEEE80211_RADIOTAP_F_FRAG: frame will be fragmented if longer than the
current fragmentation threshold.
* IEEE80211_RADIOTAP_TX_FLAGS
IEEE80211_RADIOTAP_F_TX_NOACK: frame should be sent without waiting for
an ACK even if it is a unicast frame
The injection code can also skip all other currently defined radiotap fields
facilitating replay of captured radiotap headers directly.

4
Documentation/networking/netdevices.txt
View File

@ -73,7 +73,7 @@ dev->hard_start_xmit:
has to lock by itself when needed. It is recommended to use a try lock
for this and return NETDEV_TX_LOCKED when the spin lock fails.
The locking there should also properly protect against
set_multicast_list. Note that the use of NETIF_F_LLTX is deprecated.
set_rx_mode. Note that the use of NETIF_F_LLTX is deprecated.
Don't use it for new drivers.
Context: Process with BHs disabled or BH (timer),
@ -92,7 +92,7 @@ dev->tx_timeout:
Context: BHs disabled
Notes: netif_queue_stopped() is guaranteed true
dev->set_multicast_list:
dev->set_rx_mode:
Synchronization: netif_tx_lock spinlock.
Context: BHs disabled

14
Documentation/networking/scaling.txt
View File

@ -27,7 +27,7 @@ applying a filter to each packet that assigns it to one of a small number
of logical flows. Packets for each flow are steered to a separate receive
queue, which in turn can be processed by separate CPUs. This mechanism is
generally known as “Receive-side Scaling” (RSS). The goal of RSS and
the other scaling techniques to increase performance uniformly.
the other scaling techniques is to increase performance uniformly.
Multi-queue distribution can also be used for traffic prioritization, but
that is not the focus of these techniques.
@ -73,7 +73,7 @@ of queues to IRQs can be determined from /proc/interrupts. By default,
an IRQ may be handled on any CPU. Because a non-negligible part of packet
processing takes place in receive interrupt handling, it is advantageous
to spread receive interrupts between CPUs. To manually adjust the IRQ
affinity of each interrupt see Documentation/IRQ-affinity. Some systems
affinity of each interrupt see Documentation/IRQ-affinity.txt. Some systems
will be running irqbalance, a daemon that dynamically optimizes IRQ
assignments and as a result may override any manual settings.
@ -186,10 +186,10 @@ are steered using plain RPS. Multiple table entries may point to the
same CPU. Indeed, with many flows and few CPUs, it is very likely that
a single application thread handles flows with many different flow hashes.
rps_sock_table is a global flow table that contains the *desired* CPU for
flows: the CPU that is currently processing the flow in userspace. Each
table value is a CPU index that is updated during calls to recvmsg and
sendmsg (specifically, inet_recvmsg(), inet_sendmsg(), inet_sendpage()
rps_sock_flow_table is a global flow table that contains the *desired* CPU
for flows: the CPU that is currently processing the flow in userspace.
Each table value is a CPU index that is updated during calls to recvmsg
and sendmsg (specifically, inet_recvmsg(), inet_sendmsg(), inet_sendpage()
and tcp_splice_read()).
When the scheduler moves a thread to a new CPU while it has outstanding
@ -243,7 +243,7 @@ configured. The number of entries in the global flow table is set through:
The number of entries in the per-queue flow table are set through:
/sys/class/net/<dev>/queues/tx-<n>/rps_flow_cnt
/sys/class/net/<dev>/queues/rx-<n>/rps_flow_cnt
== Suggested Configuration

44
Documentation/networking/stmmac.txt
View File

@ -76,7 +76,16 @@ core.
4.5) DMA descriptors
Driver handles both normal and enhanced descriptors. The latter has been only
tested on DWC Ether MAC 10/100/1000 Universal version 3.41a.
tested on DWC Ether MAC 10/100/1000 Universal version 3.41a and later.
STMMAC supports DMA descriptor to operate both in dual buffer (RING)
and linked-list(CHAINED) mode. In RING each descriptor points to two
data buffer pointers whereas in CHAINED mode they point to only one data
buffer pointer. RING mode is the default.
In CHAINED mode each descriptor will have pointer to next descriptor in
the list, hence creating the explicit chaining in the descriptor itself,
whereas such explicit chaining is not possible in RING mode.
4.6) Ethtool support
Ethtool is supported. Driver statistics and internal errors can be taken using:
@ -235,7 +244,38 @@ reset procedure etc).
o enh_desc.c: functions for handling enhanced descriptors
o norm_desc.c: functions for handling normal descriptors
5) TODO:
5) Debug Information
The driver exports many information i.e. internal statistics,
debug information, MAC and DMA registers etc.
These can be read in several ways depending on the
type of the information actually needed.
For example a user can be use the ethtool support
to get statistics: e.g. using: ethtool -S ethX
(that shows the Management counters (MMC) if supported)
or sees the MAC/DMA registers: e.g. using: ethtool -d ethX
Compiling the Kernel with CONFIG_DEBUG_FS and enabling the
STMMAC_DEBUG_FS option the driver will export the following
debugfs entries:
/sys/kernel/debug/stmmaceth/descriptors_status
To show the DMA TX/RX descriptor rings
Developer can also use the "debug" module parameter to get
further debug information.
In the end, there are other macros (that cannot be enabled
via menuconfig) to turn-on the RX/TX DMA debugging,
specific MAC core debug printk etc. Others to enable the
debug in the TX and RX processes.
All these are only useful during the developing stage
and should never enabled inside the code for general usage.
In fact, these can generate an huge amount of debug messages.
6) TODO:
o XGMAC is not supported.
o Review the timer optimisation code to use an embedded device that will be
available in new chip generations.

950
Documentation/pinctrl.txt Normal file
View File

@ -0,0 +1,950 @@
PINCTRL (PIN CONTROL) subsystem
This document outlines the pin control subsystem in Linux
This subsystem deals with:
- Enumerating and naming controllable pins
- Multiplexing of pins, pads, fingers (etc) see below for details
The intention is to also deal with:
- Software-controlled biasing and driving mode specific pins, such as
pull-up/down, open drain etc, load capacitance configuration when controlled
by software, etc.
Top-level interface
===================
Definition of PIN CONTROLLER:
- A pin controller is a piece of hardware, usually a set of registers, that
can control PINs. It may be able to multiplex, bias, set load capacitance,
set drive strength etc for individual pins or groups of pins.
Definition of PIN:
- PINS are equal to pads, fingers, balls or whatever packaging input or
output line you want to control and these are denoted by unsigned integers
in the range 0..maxpin. This numberspace is local to each PIN CONTROLLER, so
there may be several such number spaces in a system. This pin space may
be sparse - i.e. there may be gaps in the space with numbers where no
pin exists.
When a PIN CONTROLLER is instatiated, it will register a descriptor to the
pin control framework, and this descriptor contains an array of pin descriptors
describing the pins handled by this specific pin controller.
Here is an example of a PGA (Pin Grid Array) chip seen from underneath:
A B C D E F G H
8 o o o o o o o o
7 o o o o o o o o
6 o o o o o o o o
5 o o o o o o o o
4 o o o o o o o o
3 o o o o o o o o
2 o o o o o o o o
1 o o o o o o o o
To register a pin controller and name all the pins on this package we can do
this in our driver:
#include <linux/pinctrl/pinctrl.h>
const struct pinctrl_pin_desc __refdata foo_pins[] = {
PINCTRL_PIN(0, "A1"),
PINCTRL_PIN(1, "A2"),
PINCTRL_PIN(2, "A3"),
...
PINCTRL_PIN(61, "H6"),
PINCTRL_PIN(62, "H7"),
PINCTRL_PIN(63, "H8"),
};
static struct pinctrl_desc foo_desc = {
.name = "foo",
.pins = foo_pins,
.npins = ARRAY_SIZE(foo_pins),
.maxpin = 63,
.owner = THIS_MODULE,
};
int __init foo_probe(void)
{
struct pinctrl_dev *pctl;
pctl = pinctrl_register(&foo_desc, <PARENT>, NULL);
if (IS_ERR(pctl))
pr_err("could not register foo pin driver\n");
}
Pins usually have fancier names than this. You can find these in the dataheet
for your chip. Notice that the core pinctrl.h file provides a fancy macro
called PINCTRL_PIN() to create the struct entries. As you can see I enumerated
the pins from 0 in the upper left corner to 63 in the lower right corner,
this enumeration was arbitrarily chosen, in practice you need to think
through your numbering system so that it matches the layout of registers
and such things in your driver, or the code may become complicated. You must
also consider matching of offsets to the GPIO ranges that may be handled by
the pin controller.
For a padring with 467 pads, as opposed to actual pins, I used an enumeration
like this, walking around the edge of the chip, which seems to be industry
standard too (all these pads had names, too):
0 ..... 104
466 105
. .
. .
358 224
357 .... 225
Pin groups
==========
Many controllers need to deal with groups of pins, so the pin controller
subsystem has a mechanism for enumerating groups of pins and retrieving the
actual enumerated pins that are part of a certain group.
For example, say that we have a group of pins dealing with an SPI interface
on { 0, 8, 16, 24 }, and a group of pins dealing with an I2C interface on pins
on { 24, 25 }.
These two groups are presented to the pin control subsystem by implementing
some generic pinctrl_ops like this:
#include <linux/pinctrl/pinctrl.h>
struct foo_group {
const char *name;
const unsigned int *pins;
const unsigned num_pins;
};
static unsigned int spi0_pins[] = { 0, 8, 16, 24 };
static unsigned int i2c0_pins[] = { 24, 25 };
static const struct foo_group foo_groups[] = {
{
.name = "spi0_grp",
.pins = spi0_pins,
.num_pins = ARRAY_SIZE(spi0_pins),
},
{
.name = "i2c0_grp",
.pins = i2c0_pins,
.num_pins = ARRAY_SIZE(i2c0_pins),
},
};
static int foo_list_groups(struct pinctrl_dev *pctldev, unsigned selector)
{
if (selector >= ARRAY_SIZE(foo_groups))
return -EINVAL;
return 0;
}
static const char *foo_get_group_name(struct pinctrl_dev *pctldev,
unsigned selector)
{
return foo_groups[selector].name;
}
static int foo_get_group_pins(struct pinctrl_dev *pctldev, unsigned selector,
unsigned ** const pins,
unsigned * const num_pins)
{
*pins = (unsigned *) foo_groups[selector].pins;
*num_pins = foo_groups[selector].num_pins;
return 0;
}
static struct pinctrl_ops foo_pctrl_ops = {
.list_groups = foo_list_groups,
.get_group_name = foo_get_group_name,
.get_group_pins = foo_get_group_pins,
};
static struct pinctrl_desc foo_desc = {
...
.pctlops = &foo_pctrl_ops,
};
The pin control subsystem will call the .list_groups() function repeatedly
beginning on 0 until it returns non-zero to determine legal selectors, then
it will call the other functions to retrieve the name and pins of the group.
Maintaining the data structure of the groups is up to the driver, this is
just a simple example - in practice you may need more entries in your group
structure, for example specific register ranges associated with each group
and so on.
Interaction with the GPIO subsystem
===================================
The GPIO drivers may want to perform operations of various types on the same
physical pins that are also registered as pin controller pins.
Since the pin controller subsystem have its pinspace local to the pin
controller we need a mapping so that the pin control subsystem can figure out
which pin controller handles control of a certain GPIO pin. Since a single
pin controller may be muxing several GPIO ranges (typically SoCs that have
one set of pins but internally several GPIO silicon blocks, each modeled as
a struct gpio_chip) any number of GPIO ranges can be added to a pin controller
instance like this:
struct gpio_chip chip_a;
struct gpio_chip chip_b;
static struct pinctrl_gpio_range gpio_range_a = {
.name = "chip a",
.id = 0,
.base = 32,
.npins = 16,
.gc = &chip_a;
};
static struct pinctrl_gpio_range gpio_range_a = {
.name = "chip b",
.id = 0,
.base = 48,
.npins = 8,
.gc = &chip_b;
};
{
struct pinctrl_dev *pctl;
...
pinctrl_add_gpio_range(pctl, &gpio_range_a);
pinctrl_add_gpio_range(pctl, &gpio_range_b);
}
So this complex system has one pin controller handling two different
GPIO chips. Chip a has 16 pins and chip b has 8 pins. They are mapped in
the global GPIO pin space at:
chip a: [32 .. 47]
chip b: [48 .. 55]
When GPIO-specific functions in the pin control subsystem are called, these
ranges will be used to look up the apropriate pin controller by inspecting
and matching the pin to the pin ranges across all controllers. When a
pin controller handling the matching range is found, GPIO-specific functions
will be called on that specific pin controller.
For all functionalities dealing with pin biasing, pin muxing etc, the pin
controller subsystem will subtract the range's .base offset from the passed
in gpio pin number, and pass that on to the pin control driver, so the driver
will get an offset into its handled number range. Further it is also passed
the range ID value, so that the pin controller knows which range it should
deal with.
For example: if a user issues pinctrl_gpio_set_foo(50), the pin control
subsystem will find that the second range on this pin controller matches,
subtract the base 48 and call the
pinctrl_driver_gpio_set_foo(pinctrl, range, 2) where the latter function has
this signature:
int pinctrl_driver_gpio_set_foo(struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *rangeid,
unsigned offset);
Now the driver knows that we want to do some GPIO-specific operation on the
second GPIO range handled by "chip b", at offset 2 in that specific range.
(If the GPIO subsystem is ever refactored to use a local per-GPIO controller
pin space, this mapping will need to be augmented accordingly.)
PINMUX interfaces
=================
These calls use the pinmux_* naming prefix. No other calls should use that
prefix.
What is pinmuxing?
==================
PINMUX, also known as padmux, ballmux, alternate functions or mission modes
is a way for chip vendors producing some kind of electrical packages to use
a certain physical pin (ball, pad, finger, etc) for multiple mutually exclusive
functions, depending on the application. By "application" in this context
we usually mean a way of soldering or wiring the package into an electronic
system, even though the framework makes it possible to also change the function
at runtime.
Here is an example of a PGA (Pin Grid Array) chip seen from underneath:
A B C D E F G H
+---+
8 | o | o o o o o o o
| |
7 | o | o o o o o o o
| |
6 | o | o o o o o o o
+---+---+
5 | o | o | o o o o o o
+---+---+ +---+
4 o o o o o o | o | o
| |
3 o o o o o o | o | o
| |
2 o o o o o o | o | o
+-------+-------+-------+---+---+
1 | o o | o o | o o | o | o |
+-------+-------+-------+---+---+
This is not tetris. The game to think of is chess. Not all PGA/BGA packages
are chessboard-like, big ones have "holes" in some arrangement according to
different design patterns, but we're using this as a simple example. Of the
pins you see some will be taken by things like a few VCC and GND to feed power
to the chip, and quite a few will be taken by large ports like an external
memory interface. The remaining pins will often be subject to pin multiplexing.
The example 8x8 PGA package above will have pin numbers 0 thru 63 assigned to
its physical pins. It will name the pins { A1, A2, A3 ... H6, H7, H8 } using
pinctrl_register_pins() and a suitable data set as shown earlier.
In this 8x8 BGA package the pins { A8, A7, A6, A5 } can be used as an SPI port
(these are four pins: CLK, RXD, TXD, FRM). In that case, pin B5 can be used as
some general-purpose GPIO pin. However, in another setting, pins { A5, B5 } can
be used as an I2C port (these are just two pins: SCL, SDA). Needless to say,
we cannot use the SPI port and I2C port at the same time. However in the inside
of the package the silicon performing the SPI logic can alternatively be routed
out on pins { G4, G3, G2, G1 }.
On the botton row at { A1, B1, C1, D1, E1, F1, G1, H1 } we have something
special - it's an external MMC bus that can be 2, 4 or 8 bits wide, and it will
consume 2, 4 or 8 pins respectively, so either { A1, B1 } are taken or
{ A1, B1, C1, D1 } or all of them. If we use all 8 bits, we cannot use the SPI
port on pins { G4, G3, G2, G1 } of course.
This way the silicon blocks present inside the chip can be multiplexed "muxed"
out on different pin ranges. Often contemporary SoC (systems on chip) will
contain several I2C, SPI, SDIO/MMC, etc silicon blocks that can be routed to
different pins by pinmux settings.
Since general-purpose I/O pins (GPIO) are typically always in shortage, it is
common to be able to use almost any pin as a GPIO pin if it is not currently
in use by some other I/O port.
Pinmux conventions
==================
The purpose of the pinmux functionality in the pin controller subsystem is to
abstract and provide pinmux settings to the devices you choose to instantiate
in your machine configuration. It is inspired by the clk, GPIO and regulator
subsystems, so devices will request their mux setting, but it's also possible
to request a single pin for e.g. GPIO.
Definitions:
- FUNCTIONS can be switched in and out by a driver residing with the pin
control subsystem in the drivers/pinctrl/* directory of the kernel. The
pin control driver knows the possible functions. In the example above you can
identify three pinmux functions, one for spi, one for i2c and one for mmc.
- FUNCTIONS are assumed to be enumerable from zero in a one-dimensional array.
In this case the array could be something like: { spi0, i2c0, mmc0 }
for the three available functions.
- FUNCTIONS have PIN GROUPS as defined on the generic level - so a certain
function is *always* associated with a certain set of pin groups, could
be just a single one, but could also be many. In the example above the
function i2c is associated with the pins { A5, B5 }, enumerated as
{ 24, 25 } in the controller pin space.
The Function spi is associated with pin groups { A8, A7, A6, A5 }
and { G4, G3, G2, G1 }, which are enumerated as { 0, 8, 16, 24 } and
{ 38, 46, 54, 62 } respectively.
Group names must be unique per pin controller, no two groups on the same
controller may have the same name.
- The combination of a FUNCTION and a PIN GROUP determine a certain function
for a certain set of pins. The knowledge of the functions and pin groups
and their machine-specific particulars are kept inside the pinmux driver,
from the outside only the enumerators are known, and the driver core can:
- Request the name of a function with a certain selector (>= 0)
- A list of groups associated with a certain function
- Request that a certain group in that list to be activated for a certain
function
As already described above, pin groups are in turn self-descriptive, so
the core will retrieve the actual pin range in a certain group from the
driver.
- FUNCTIONS and GROUPS on a certain PIN CONTROLLER are MAPPED to a certain
device by the board file, device tree or similar machine setup configuration
mechanism, similar to how regulators are connected to devices, usually by
name. Defining a pin controller, function and group thus uniquely identify
the set of pins to be used by a certain device. (If only one possible group
of pins is available for the function, no group name need to be supplied -
the core will simply select the first and only group available.)
In the example case we can define that this particular machine shall
use device spi0 with pinmux function fspi0 group gspi0 and i2c0 on function
fi2c0 group gi2c0, on the primary pin controller, we get mappings
like these:
{
{"map-spi0", spi0, pinctrl0, fspi0, gspi0},
{"map-i2c0", i2c0, pinctrl0, fi2c0, gi2c0}
}
Every map must be assigned a symbolic name, pin controller and function.
The group is not compulsory - if it is omitted the first group presented by
the driver as applicable for the function will be selected, which is
useful for simple cases.
The device name is present in map entries tied to specific devices. Maps
without device names are referred to as SYSTEM pinmuxes, such as can be taken
by the machine implementation on boot and not tied to any specific device.
It is possible to map several groups to the same combination of device,
pin controller and function. This is for cases where a certain function on
a certain pin controller may use different sets of pins in different
configurations.
- PINS for a certain FUNCTION using a certain PIN GROUP on a certain
PIN CONTROLLER are provided on a first-come first-serve basis, so if some
other device mux setting or GPIO pin request has already taken your physical
pin, you will be denied the use of it. To get (activate) a new setting, the
old one has to be put (deactivated) first.
Sometimes the documentation and hardware registers will be oriented around
pads (or "fingers") rather than pins - these are the soldering surfaces on the
silicon inside the package, and may or may not match the actual number of
pins/balls underneath the capsule. Pick some enumeration that makes sense to
you. Define enumerators only for the pins you can control if that makes sense.
Assumptions:
We assume that the number possible function maps to pin groups is limited by
the hardware. I.e. we assume that there is no system where any function can be
mapped to any pin, like in a phone exchange. So the available pins groups for
a certain function will be limited to a few choices (say up to eight or so),
not hundreds or any amount of choices. This is the characteristic we have found
by inspecting available pinmux hardware, and a necessary assumption since we
expect pinmux drivers to present *all* possible function vs pin group mappings
to the subsystem.
Pinmux drivers
==============
The pinmux core takes care of preventing conflicts on pins and calling
the pin controller driver to execute different settings.
It is the responsibility of the pinmux driver to impose further restrictions
(say for example infer electronic limitations due to load etc) to determine
whether or not the requested function can actually be allowed, and in case it
is possible to perform the requested mux setting, poke the hardware so that
this happens.
Pinmux drivers are required to supply a few callback functions, some are
optional. Usually the enable() and disable() functions are implemented,
writing values into some certain registers to activate a certain mux setting
for a certain pin.
A simple driver for the above example will work by setting bits 0, 1, 2, 3 or 4
into some register named MUX to select a certain function with a certain
group of pins would work something like this:
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinmux.h>
struct foo_group {
const char *name;
const unsigned int *pins;
const unsigned num_pins;
};
static const unsigned spi0_0_pins[] = { 0, 8, 16, 24 };
static const unsigned spi0_1_pins[] = { 38, 46, 54, 62 };
static const unsigned i2c0_pins[] = { 24, 25 };
static const unsigned mmc0_1_pins[] = { 56, 57 };
static const unsigned mmc0_2_pins[] = { 58, 59 };
static const unsigned mmc0_3_pins[] = { 60, 61, 62, 63 };
static const struct foo_group foo_groups[] = {
{
.name = "spi0_0_grp",
.pins = spi0_0_pins,
.num_pins = ARRAY_SIZE(spi0_0_pins),
},
{
.name = "spi0_1_grp",
.pins = spi0_1_pins,
.num_pins = ARRAY_SIZE(spi0_1_pins),
},
{
.name = "i2c0_grp",
.pins = i2c0_pins,
.num_pins = ARRAY_SIZE(i2c0_pins),
},
{
.name = "mmc0_1_grp",
.pins = mmc0_1_pins,
.num_pins = ARRAY_SIZE(mmc0_1_pins),
},
{
.name = "mmc0_2_grp",
.pins = mmc0_2_pins,
.num_pins = ARRAY_SIZE(mmc0_2_pins),
},
{
.name = "mmc0_3_grp",
.pins = mmc0_3_pins,
.num_pins = ARRAY_SIZE(mmc0_3_pins),
},
};
static int foo_list_groups(struct pinctrl_dev *pctldev, unsigned selector)
{
if (selector >= ARRAY_SIZE(foo_groups))
return -EINVAL;
return 0;
}
static const char *foo_get_group_name(struct pinctrl_dev *pctldev,
unsigned selector)
{
return foo_groups[selector].name;
}
static int foo_get_group_pins(struct pinctrl_dev *pctldev, unsigned selector,
unsigned ** const pins,
unsigned * const num_pins)
{
*pins = (unsigned *) foo_groups[selector].pins;
*num_pins = foo_groups[selector].num_pins;
return 0;
}
static struct pinctrl_ops foo_pctrl_ops = {
.list_groups = foo_list_groups,
.get_group_name = foo_get_group_name,
.get_group_pins = foo_get_group_pins,
};
struct foo_pmx_func {
const char *name;
const char * const *groups;
const unsigned num_groups;
};
static const char * const spi0_groups[] = { "spi0_1_grp" };
static const char * const i2c0_groups[] = { "i2c0_grp" };
static const char * const mmc0_groups[] = { "mmc0_1_grp", "mmc0_2_grp",
"mmc0_3_grp" };
static const struct foo_pmx_func foo_functions[] = {
{
.name = "spi0",
.groups = spi0_groups,
.num_groups = ARRAY_SIZE(spi0_groups),
},
{
.name = "i2c0",
.groups = i2c0_groups,
.num_groups = ARRAY_SIZE(i2c0_groups),
},
{
.name = "mmc0",
.groups = mmc0_groups,
.num_groups = ARRAY_SIZE(mmc0_groups),
},
};
int foo_list_funcs(struct pinctrl_dev *pctldev, unsigned selector)
{
if (selector >= ARRAY_SIZE(foo_functions))
return -EINVAL;
return 0;
}
const char *foo_get_fname(struct pinctrl_dev *pctldev, unsigned selector)
{
return myfuncs[selector].name;
}
static int foo_get_groups(struct pinctrl_dev *pctldev, unsigned selector,
const char * const **groups,
unsigned * const num_groups)
{
*groups = foo_functions[selector].groups;
*num_groups = foo_functions[selector].num_groups;
return 0;
}
int foo_enable(struct pinctrl_dev *pctldev, unsigned selector,
unsigned group)
{
u8 regbit = (1 << group);
writeb((readb(MUX)|regbit), MUX)
return 0;
}
int foo_disable(struct pinctrl_dev *pctldev, unsigned selector,
unsigned group)
{
u8 regbit = (1 << group);
writeb((readb(MUX) & ~(regbit)), MUX)
return 0;
}
struct pinmux_ops foo_pmxops = {
.list_functions = foo_list_funcs,
.get_function_name = foo_get_fname,
.get_function_groups = foo_get_groups,
.enable = foo_enable,
.disable = foo_disable,
};
/* Pinmux operations are handled by some pin controller */
static struct pinctrl_desc foo_desc = {
...
.pctlops = &foo_pctrl_ops,
.pmxops = &foo_pmxops,
};
In the example activating muxing 0 and 1 at the same time setting bits
0 and 1, uses one pin in common so they would collide.
The beauty of the pinmux subsystem is that since it keeps track of all
pins and who is using them, it will already have denied an impossible
request like that, so the driver does not need to worry about such
things - when it gets a selector passed in, the pinmux subsystem makes
sure no other device or GPIO assignment is already using the selected
pins. Thus bits 0 and 1 in the control register will never be set at the
same time.
All the above functions are mandatory to implement for a pinmux driver.
Pinmux interaction with the GPIO subsystem
==========================================
The function list could become long, especially if you can convert every
individual pin into a GPIO pin independent of any other pins, and then try
the approach to define every pin as a function.
In this case, the function array would become 64 entries for each GPIO
setting and then the device functions.
For this reason there is an additional function a pinmux driver can implement
to enable only GPIO on an individual pin: .gpio_request_enable(). The same
.free() function as for other functions is assumed to be usable also for
GPIO pins.
This function will pass in the affected GPIO range identified by the pin
controller core, so you know which GPIO pins are being affected by the request
operation.
Alternatively it is fully allowed to use named functions for each GPIO
pin, the pinmux_request_gpio() will attempt to obtain the function "gpioN"
where "N" is the global GPIO pin number if no special GPIO-handler is
registered.
Pinmux board/machine configuration
==================================
Boards and machines define how a certain complete running system is put
together, including how GPIOs and devices are muxed, how regulators are
constrained and how the clock tree looks. Of course pinmux settings are also
part of this.
A pinmux config for a machine looks pretty much like a simple regulator
configuration, so for the example array above we want to enable i2c and
spi on the second function mapping:
#include <linux/pinctrl/machine.h>
static struct pinmux_map pmx_mapping[] = {
{
.ctrl_dev_name = "pinctrl.0",
.function = "spi0",
.dev_name = "foo-spi.0",
},
{
.ctrl_dev_name = "pinctrl.0",
.function = "i2c0",
.dev_name = "foo-i2c.0",
},
{
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
.dev_name = "foo-mmc.0",
},
};
The dev_name here matches to the unique device name that can be used to look
up the device struct (just like with clockdev or regulators). The function name
must match a function provided by the pinmux driver handling this pin range.
As you can see we may have several pin controllers on the system and thus
we need to specify which one of them that contain the functions we wish
to map. The map can also use struct device * directly, so there is no
inherent need to use strings to specify .dev_name or .ctrl_dev_name, these
are for the situation where you do not have a handle to the struct device *,
for example if they are not yet instantiated or cumbersome to obtain.
You register this pinmux mapping to the pinmux subsystem by simply:
ret = pinmux_register_mappings(&pmx_mapping, ARRAY_SIZE(pmx_mapping));
Since the above construct is pretty common there is a helper macro to make
it even more compact which assumes you want to use pinctrl.0 and position
0 for mapping, for example:
static struct pinmux_map pmx_mapping[] = {
PINMUX_MAP_PRIMARY("I2CMAP", "i2c0", "foo-i2c.0"),
};
Complex mappings
================
As it is possible to map a function to different groups of pins an optional
.group can be specified like this:
...
{
.name = "spi0-pos-A",
.ctrl_dev_name = "pinctrl.0",
.function = "spi0",
.group = "spi0_0_grp",
.dev_name = "foo-spi.0",
},
{
.name = "spi0-pos-B",
.ctrl_dev_name = "pinctrl.0",
.function = "spi0",
.group = "spi0_1_grp",
.dev_name = "foo-spi.0",
},
...
This example mapping is used to switch between two positions for spi0 at
runtime, as described further below under the heading "Runtime pinmuxing".
Further it is possible to match several groups of pins to the same function
for a single device, say for example in the mmc0 example above, where you can
additively expand the mmc0 bus from 2 to 4 to 8 pins. If we want to use all
three groups for a total of 2+2+4 = 8 pins (for an 8-bit MMC bus as is the
case), we define a mapping like this:
...
{
.name "2bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
.group = "mmc0_0_grp",
.dev_name = "foo-mmc.0",
},
{
.name "4bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
.group = "mmc0_0_grp",
.dev_name = "foo-mmc.0",
},
{
.name "4bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
.group = "mmc0_1_grp",
.dev_name = "foo-mmc.0",
},
{
.name "8bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
.group = "mmc0_0_grp",
.dev_name = "foo-mmc.0",
},
{
.name "8bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
.group = "mmc0_1_grp",
.dev_name = "foo-mmc.0",
},
{
.name "8bit"
.ctrl_dev_name = "pinctrl.0",
.function = "mmc0",
.group = "mmc0_2_grp",
.dev_name = "foo-mmc.0",
},
...
The result of grabbing this mapping from the device with something like
this (see next paragraph):
pmx = pinmux_get(&device, "8bit");
Will be that you activate all the three bottom records in the mapping at
once. Since they share the same name, pin controller device, funcion and
device, and since we allow multiple groups to match to a single device, they
all get selected, and they all get enabled and disable simultaneously by the
pinmux core.
Pinmux requests from drivers
============================
Generally it is discouraged to let individual drivers get and enable pinmuxes.
So if possible, handle the pinmuxes in platform code or some other place where
you have access to all the affected struct device * pointers. In some cases
where a driver needs to switch between different mux mappings at runtime
this is not possible.
A driver may request a certain mux to be activated, usually just the default
mux like this:
#include <linux/pinctrl/pinmux.h>
struct foo_state {
struct pinmux *pmx;
...
};
foo_probe()
{
/* Allocate a state holder named "state" etc */
struct pinmux pmx;
pmx = pinmux_get(&device, NULL);
if IS_ERR(pmx)
return PTR_ERR(pmx);
pinmux_enable(pmx);
state->pmx = pmx;
}
foo_remove()
{
pinmux_disable(state->pmx);
pinmux_put(state->pmx);
}
If you want to grab a specific mux mapping and not just the first one found for
this device you can specify a specific mapping name, for example in the above
example the second i2c0 setting: pinmux_get(&device, "spi0-pos-B");
This get/enable/disable/put sequence can just as well be handled by bus drivers
if you don't want each and every driver to handle it and you know the
arrangement on your bus.
The semantics of the get/enable respective disable/put is as follows:
- pinmux_get() is called in process context to reserve the pins affected with
a certain mapping and set up the pinmux core and the driver. It will allocate
a struct from the kernel memory to hold the pinmux state.
- pinmux_enable()/pinmux_disable() is quick and can be called from fastpath
(irq context) when you quickly want to set up/tear down the hardware muxing
when running a device driver. Usually it will just poke some values into a
register.
- pinmux_disable() is called in process context to tear down the pin requests
and release the state holder struct for the mux setting.
Usually the pinmux core handled the get/put pair and call out to the device
drivers bookkeeping operations, like checking available functions and the
associated pins, whereas the enable/disable pass on to the pin controller
driver which takes care of activating and/or deactivating the mux setting by
quickly poking some registers.
The pins are allocated for your device when you issue the pinmux_get() call,
after this you should be able to see this in the debugfs listing of all pins.
System pinmux hogging
=====================
A system pinmux map entry, i.e. a pinmux setting that does not have a device
associated with it, can be hogged by the core when the pin controller is
registered. This means that the core will attempt to call pinmux_get() and
pinmux_enable() on it immediately after the pin control device has been
registered.
This is enabled by simply setting the .hog_on_boot field in the map to true,
like this:
{
.name "POWERMAP"
.ctrl_dev_name = "pinctrl.0",
.function = "power_func",
.hog_on_boot = true,
},
Since it may be common to request the core to hog a few always-applicable
mux settings on the primary pin controller, there is a convenience macro for
this:
PINMUX_MAP_PRIMARY_SYS_HOG("POWERMAP", "power_func")
This gives the exact same result as the above construction.
Runtime pinmuxing
=================
It is possible to mux a certain function in and out at runtime, say to move
an SPI port from one set of pins to another set of pins. Say for example for
spi0 in the example above, we expose two different groups of pins for the same
function, but with different named in the mapping as described under
"Advanced mapping" above. So we have two mappings named "spi0-pos-A" and
"spi0-pos-B".
This snippet first muxes the function in the pins defined by group A, enables
it, disables and releases it, and muxes it in on the pins defined by group B:
foo_switch()
{
struct pinmux pmx;
/* Enable on position A */
pmx = pinmux_get(&device, "spi0-pos-A");
if IS_ERR(pmx)
return PTR_ERR(pmx);
pinmux_enable(pmx);
/* This releases the pins again */
pinmux_disable(pmx);
pinmux_put(pmx);
/* Enable on position B */
pmx = pinmux_get(&device, "spi0-pos-B");
if IS_ERR(pmx)
return PTR_ERR(pmx);
pinmux_enable(pmx);
...
}
The above has to be done from process context.

2
Documentation/power/00-INDEX
View File

@ -26,6 +26,8 @@ s2ram.txt
- How to get suspend to ram working (and debug it when it isn't)
states.txt
- System power management states
suspend-and-cpuhotplug.txt
- Explains the interaction between Suspend-to-RAM (S3) and CPU hotplug
swsusp-and-swap-files.txt
- Using swap files with software suspend (to disk)
swsusp-dmcrypt.txt

26
Documentation/power/basic-pm-debugging.txt
View File

@ -173,7 +173,7 @@ kernel messages using the serial console. This may provide you with some
information about the reasons of the suspend (resume) failure. Alternatively,
it may be possible to use a FireWire port for debugging with firescope
(ftp://ftp.firstfloor.org/pub/ak/firescope/). On x86 it is also possible to
use the PM_TRACE mechanism documented in Documentation/s2ram.txt .
use the PM_TRACE mechanism documented in Documentation/power/s2ram.txt .
2. Testing suspend to RAM (STR)
@ -201,3 +201,27 @@ case, you may be able to search for failing drivers by following the procedure
analogous to the one described in section 1. If you find some failing drivers,
you will have to unload them every time before an STR transition (ie. before
you run s2ram), and please report the problems with them.
There is a debugfs entry which shows the suspend to RAM statistics. Here is an
example of its output.
# mount -t debugfs none /sys/kernel/debug
# cat /sys/kernel/debug/suspend_stats
success: 20
fail: 5
failed_freeze: 0
failed_prepare: 0
failed_suspend: 5
failed_suspend_noirq: 0
failed_resume: 0
failed_resume_noirq: 0
failures:
last_failed_dev: alarm
adc
last_failed_errno: -16
-16
last_failed_step: suspend
suspend
Field success means the success number of suspend to RAM, and field fail means
the failure number. Others are the failure number of different steps of suspend
to RAM. suspend_stats just lists the last 2 failed devices, error number and
failed step of suspend.

8
Documentation/power/devices.txt
View File

@ -152,7 +152,9 @@ try to use its wakeup mechanism. device_set_wakeup_enable() affects this flag;
for the most part drivers should not change its value. The initial value of
should_wakeup is supposed to be false for the majority of devices; the major
exceptions are power buttons, keyboards, and Ethernet adapters whose WoL
(wake-on-LAN) feature has been set up with ethtool.
(wake-on-LAN) feature has been set up with ethtool. It should also default
to true for devices that don't generate wakeup requests on their own but merely
forward wakeup requests from one bus to another (like PCI bridges).
Whether or not a device is capable of issuing wakeup events is a hardware
matter, and the kernel is responsible for keeping track of it. By contrast,
@ -279,10 +281,6 @@ When the system goes into the standby or memory sleep state, the phases are:
time.) Unlike the other suspend-related phases, during the prepare
phase the device tree is traversed top-down.
In addition to that, if device drivers need to allocate additional
memory to be able to hadle device suspend correctly, that should be
done in the prepare phase.
After the prepare callback method returns, no new children may be
registered below the device. The method may also prepare the device or
driver in some way for the upcoming system power transition (for

92
Documentation/power/pm_qos_interface.txt
View File

@ -4,14 +4,19 @@ This interface provides a kernel and user mode interface for registering
performance expectations by drivers, subsystems and user space applications on
one of the parameters.
Currently we have {cpu_dma_latency, network_latency, network_throughput} as the
initial set of pm_qos parameters.
Two different PM QoS frameworks are available:
1. PM QoS classes for cpu_dma_latency, network_latency, network_throughput.
2. the per-device PM QoS framework provides the API to manage the per-device latency
constraints.
Each parameters have defined units:
* latency: usec
* timeout: usec
* throughput: kbs (kilo bit / sec)
1. PM QoS framework
The infrastructure exposes multiple misc device nodes one per implemented
parameter. The set of parameters implement is defined by pm_qos_power_init()
and pm_qos_params.h. This is done because having the available parameters
@ -23,14 +28,18 @@ an aggregated target value. The aggregated target value is updated with
changes to the request list or elements of the list. Typically the
aggregated target value is simply the max or min of the request values held
in the parameter list elements.
Note: the aggregated target value is implemented as an atomic variable so that
reading the aggregated value does not require any locking mechanism.
From kernel mode the use of this interface is simple:
handle = pm_qos_add_request(param_class, target_value):
Will insert an element into the list for that identified PM_QOS class with the
void pm_qos_add_request(handle, param_class, target_value):
Will insert an element into the list for that identified PM QoS class with the
target value. Upon change to this list the new target is recomputed and any
registered notifiers are called only if the target value is now different.
Clients of pm_qos need to save the returned handle.
Clients of pm_qos need to save the returned handle for future use in other
pm_qos API functions.
void pm_qos_update_request(handle, new_target_value):
Will update the list element pointed to by the handle with the new target value
@ -42,6 +51,20 @@ Will remove the element. After removal it will update the aggregate target and
call the notification tree if the target was changed as a result of removing
the request.
int pm_qos_request(param_class):
Returns the aggregated value for a given PM QoS class.
int pm_qos_request_active(handle):
Returns if the request is still active, i.e. it has not been removed from a
PM QoS class constraints list.
int pm_qos_add_notifier(param_class, notifier):
Adds a notification callback function to the PM QoS class. The callback is
called when the aggregated value for the PM QoS class is changed.
int pm_qos_remove_notifier(int param_class, notifier):
Removes the notification callback function for the PM QoS class.
From user mode:
Only processes can register a pm_qos request. To provide for automatic
@ -63,4 +86,63 @@ To remove the user mode request for a target value simply close the device
node.
2. PM QoS per-device latency framework
For each device a list of performance requests is maintained along with
an aggregated target value. The aggregated target value is updated with
changes to the request list or elements of the list. Typically the
aggregated target value is simply the max or min of the request values held
in the parameter list elements.
Note: the aggregated target value is implemented as an atomic variable so that
reading the aggregated value does not require any locking mechanism.
From kernel mode the use of this interface is the following:
int dev_pm_qos_add_request(device, handle, value):
Will insert an element into the list for that identified device with the
target value. Upon change to this list the new target is recomputed and any
registered notifiers are called only if the target value is now different.
Clients of dev_pm_qos need to save the handle for future use in other
dev_pm_qos API functions.
int dev_pm_qos_update_request(handle, new_value):
Will update the list element pointed to by the handle with the new target value
and recompute the new aggregated target, calling the notification trees if the
target is changed.
int dev_pm_qos_remove_request(handle):
Will remove the element. After removal it will update the aggregate target and
call the notification trees if the target was changed as a result of removing
the request.
s32 dev_pm_qos_read_value(device):
Returns the aggregated value for a given device's constraints list.
Notification mechanisms:
The per-device PM QoS framework has 2 different and distinct notification trees:
a per-device notification tree and a global notification tree.
int dev_pm_qos_add_notifier(device, notifier):
Adds a notification callback function for the device.
The callback is called when the aggregated value of the device constraints list
is changed.
int dev_pm_qos_remove_notifier(device, notifier):
Removes the notification callback function for the device.
int dev_pm_qos_add_global_notifier(notifier):
Adds a notification callback function in the global notification tree of the
framework.
The callback is called when the aggregated value for any device is changed.
int dev_pm_qos_remove_global_notifier(notifier):
Removes the notification callback function from the global notification tree
of the framework.
From user mode:
No API for user space access to the per-device latency constraints is provided
yet - still under discussion.

21
Documentation/power/runtime_pm.txt
View File

@ -43,13 +43,18 @@ struct dev_pm_ops {
...
};
The ->runtime_suspend(), ->runtime_resume() and ->runtime_idle() callbacks are
executed by the PM core for either the device type, or the class (if the device
type's struct dev_pm_ops object does not exist), or the bus type (if the
device type's and class' struct dev_pm_ops objects do not exist) of the given
device (this allows device types to override callbacks provided by bus types or
classes if necessary). The bus type, device type and class callbacks are
referred to as subsystem-level callbacks in what follows.
The ->runtime_suspend(), ->runtime_resume() and ->runtime_idle() callbacks
are executed by the PM core for either the power domain, or the device type
(if the device power domain's struct dev_pm_ops does not exist), or the class
(if the device power domain's and type's struct dev_pm_ops object does not
exist), or the bus type (if the device power domain's, type's and class'
struct dev_pm_ops objects do not exist) of the given device, so the priority
order of callbacks from high to low is that power domain callbacks, device
type callbacks, class callbacks and bus type callbacks, and the high priority
one will take precedence over low priority one. The bus type, device type and
class callbacks are referred to as subsystem-level callbacks in what follows,
and generally speaking, the power domain callbacks are used for representing
power domains within a SoC.
By default, the callbacks are always invoked in process context with interrupts
enabled. However, subsystems can use the pm_runtime_irq_safe() helper function
@ -477,12 +482,14 @@ pm_runtime_autosuspend_expiration()
If pm_runtime_irq_safe() has been called for a device then the following helper
functions may also be used in interrupt context:
pm_runtime_idle()
pm_runtime_suspend()
pm_runtime_autosuspend()
pm_runtime_resume()
pm_runtime_get_sync()
pm_runtime_put_sync()
pm_runtime_put_sync_suspend()
pm_runtime_put_sync_autosuspend()
5. Runtime PM Initialization, Device Probing and Removal

275
Documentation/power/suspend-and-cpuhotplug.txt Normal file
View File

@ -0,0 +1,275 @@
Interaction of Suspend code (S3) with the CPU hotplug infrastructure
(C) 2011 Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
I. How does the regular CPU hotplug code differ from how the Suspend-to-RAM
infrastructure uses it internally? And where do they share common code?
Well, a picture is worth a thousand words... So ASCII art follows :-)
[This depicts the current design in the kernel, and focusses only on the
interactions involving the freezer and CPU hotplug and also tries to explain
the locking involved. It outlines the notifications involved as well.
But please note that here, only the call paths are illustrated, with the aim
of describing where they take different paths and where they share code.
What happens when regular CPU hotplug and Suspend-to-RAM race with each other
is not depicted here.]
On a high level, the suspend-resume cycle goes like this:
|Freeze| -> |Disable nonboot| -> |Do suspend| -> |Enable nonboot| -> |Thaw |
|tasks | | cpus | | | | cpus | |tasks|
More details follow:
Suspend call path
-----------------
Write 'mem' to
/sys/power/state
syfs file
|
v
Acquire pm_mutex lock
|
v
Send PM_SUSPEND_PREPARE
notifications
|
v
Freeze tasks
|
|
v
disable_nonboot_cpus()
/* start */
|
v
Acquire cpu_add_remove_lock
|
v
Iterate over CURRENTLY
online CPUs
|
|
| ----------
v | L
======> _cpu_down() |
| [This takes cpuhotplug.lock |
Common | before taking down the CPU |
code | and releases it when done] | O
| While it is at it, notifications |
| are sent when notable events occur, |
======> by running all registered callbacks. |
| | O
| |
| |
v |
Note down these cpus in | P
frozen_cpus mask ----------
|
v
Disable regular cpu hotplug
by setting cpu_hotplug_disabled=1
|
v
Release cpu_add_remove_lock
|
v
/* disable_nonboot_cpus() complete */
|
v
Do suspend
Resuming back is likewise, with the counterparts being (in the order of
execution during resume):
* enable_nonboot_cpus() which involves:
| Acquire cpu_add_remove_lock
| Reset cpu_hotplug_disabled to 0, thereby enabling regular cpu hotplug
| Call _cpu_up() [for all those cpus in the frozen_cpus mask, in a loop]
| Release cpu_add_remove_lock
v
* thaw tasks
* send PM_POST_SUSPEND notifications
* Release pm_mutex lock.
It is to be noted here that the pm_mutex lock is acquired at the very
beginning, when we are just starting out to suspend, and then released only
after the entire cycle is complete (i.e., suspend + resume).
Regular CPU hotplug call path
-----------------------------
Write 0 (or 1) to
/sys/devices/system/cpu/cpu*/online
sysfs file
|
|
v
cpu_down()
|
v
Acquire cpu_add_remove_lock
|
v
If cpu_hotplug_disabled is 1
return gracefully
|
|
v
======> _cpu_down()
| [This takes cpuhotplug.lock
Common | before taking down the CPU
code | and releases it when done]
| While it is at it, notifications
| are sent when notable events occur,
======> by running all registered callbacks.
|
|
v
Release cpu_add_remove_lock
[That's it!, for
regular CPU hotplug]
So, as can be seen from the two diagrams (the parts marked as "Common code"),
regular CPU hotplug and the suspend code path converge at the _cpu_down() and
_cpu_up() functions. They differ in the arguments passed to these functions,
in that during regular CPU hotplug, 0 is passed for the 'tasks_frozen'
argument. But during suspend, since the tasks are already frozen by the time
the non-boot CPUs are offlined or onlined, the _cpu_*() functions are called
with the 'tasks_frozen' argument set to 1.
[See below for some known issues regarding this.]
Important files and functions/entry points:
------------------------------------------
kernel/power/process.c : freeze_processes(), thaw_processes()
kernel/power/suspend.c : suspend_prepare(), suspend_enter(), suspend_finish()
kernel/cpu.c: cpu_[up|down](), _cpu_[up|down](), [disable|enable]_nonboot_cpus()
II. What are the issues involved in CPU hotplug?
-------------------------------------------
There are some interesting situations involving CPU hotplug and microcode
update on the CPUs, as discussed below:
[Please bear in mind that the kernel requests the microcode images from
userspace, using the request_firmware() function defined in
drivers/base/firmware_class.c]
a. When all the CPUs are identical:
This is the most common situation and it is quite straightforward: we want
to apply the same microcode revision to each of the CPUs.
To give an example of x86, the collect_cpu_info() function defined in
arch/x86/kernel/microcode_core.c helps in discovering the type of the CPU
and thereby in applying the correct microcode revision to it.
But note that the kernel does not maintain a common microcode image for the
all CPUs, in order to handle case 'b' described below.
b. When some of the CPUs are different than the rest:
In this case since we probably need to apply different microcode revisions
to different CPUs, the kernel maintains a copy of the correct microcode
image for each CPU (after appropriate CPU type/model discovery using
functions such as collect_cpu_info()).
c. When a CPU is physically hot-unplugged and a new (and possibly different
type of) CPU is hot-plugged into the system:
In the current design of the kernel, whenever a CPU is taken offline during
a regular CPU hotplug operation, upon receiving the CPU_DEAD notification
(which is sent by the CPU hotplug code), the microcode update driver's
callback for that event reacts by freeing the kernel's copy of the
microcode image for that CPU.
Hence, when a new CPU is brought online, since the kernel finds that it
doesn't have the microcode image, it does the CPU type/model discovery
afresh and then requests the userspace for the appropriate microcode image
for that CPU, which is subsequently applied.
For example, in x86, the mc_cpu_callback() function (which is the microcode
update driver's callback registered for CPU hotplug events) calls
microcode_update_cpu() which would call microcode_init_cpu() in this case,
instead of microcode_resume_cpu() when it finds that the kernel doesn't
have a valid microcode image. This ensures that the CPU type/model
discovery is performed and the right microcode is applied to the CPU after
getting it from userspace.
d. Handling microcode update during suspend/hibernate:
Strictly speaking, during a CPU hotplug operation which does not involve
physically removing or inserting CPUs, the CPUs are not actually powered
off during a CPU offline. They are just put to the lowest C-states possible.
Hence, in such a case, it is not really necessary to re-apply microcode
when the CPUs are brought back online, since they wouldn't have lost the
image during the CPU offline operation.
This is the usual scenario encountered during a resume after a suspend.
However, in the case of hibernation, since all the CPUs are completely
powered off, during restore it becomes necessary to apply the microcode
images to all the CPUs.
[Note that we don't expect someone to physically pull out nodes and insert
nodes with a different type of CPUs in-between a suspend-resume or a
hibernate/restore cycle.]
In the current design of the kernel however, during a CPU offline operation
as part of the suspend/hibernate cycle (the CPU_DEAD_FROZEN notification),
the existing copy of microcode image in the kernel is not freed up.
And during the CPU online operations (during resume/restore), since the
kernel finds that it already has copies of the microcode images for all the
CPUs, it just applies them to the CPUs, avoiding any re-discovery of CPU
type/model and the need for validating whether the microcode revisions are
right for the CPUs or not (due to the above assumption that physical CPU
hotplug will not be done in-between suspend/resume or hibernate/restore
cycles).
III. Are there any known problems when regular CPU hotplug and suspend race
with each other?
Yes, they are listed below:
1. When invoking regular CPU hotplug, the 'tasks_frozen' argument passed to
the _cpu_down() and _cpu_up() functions is *always* 0.
This might not reflect the true current state of the system, since the
tasks could have been frozen by an out-of-band event such as a suspend
operation in progress. Hence, it will lead to wrong notifications being
sent during the cpu online/offline events (eg, CPU_ONLINE notification
instead of CPU_ONLINE_FROZEN) which in turn will lead to execution of
inappropriate code by the callbacks registered for such CPU hotplug events.
2. If a regular CPU hotplug stress test happens to race with the freezer due
to a suspend operation in progress at the same time, then we could hit the
situation described below:
* A regular cpu online operation continues its journey from userspace
into the kernel, since the freezing has not yet begun.
* Then freezer gets to work and freezes userspace.
* If cpu online has not yet completed the microcode update stuff by now,
it will now start waiting on the frozen userspace in the
TASK_UNINTERRUPTIBLE state, in order to get the microcode image.
* Now the freezer continues and tries to freeze the remaining tasks. But
due to this wait mentioned above, the freezer won't be able to freeze
the cpu online hotplug task and hence freezing of tasks fails.
As a result of this task freezing failure, the suspend operation gets
aborted.

3
Documentation/power/userland-swsusp.txt
View File

@ -77,7 +77,8 @@ SNAPSHOT_SET_SWAP_AREA - set the resume partition and the offset (in <PAGE_SIZE>
resume_swap_area, as defined in kernel/power/suspend_ioctls.h,
containing the resume device specification and the offset); for swap
partitions the offset is always 0, but it is different from zero for
swap files (see Documentation/swsusp-and-swap-files.txt for details).
swap files (see Documentation/power/swsusp-and-swap-files.txt for
details).
SNAPSHOT_PLATFORM_SUPPORT - enable/disable the hibernation platform support,
depending on the argument value (enable, if the argument is nonzero)

3
Documentation/rfkill.txt
View File

@ -117,5 +117,4 @@ The contents of these variables corresponds to the "name", "state" and
"type" sysfs files explained above.
For further details consult Documentation/ABI/stable/dev-rfkill and
Documentation/ABI/stable/sysfs-class-rfkill.
For further details consult Documentation/ABI/stable/sysfs-class-rfkill.

122
Documentation/scheduler/sched-bwc.txt Normal file
View File

@ -0,0 +1,122 @@
CFS Bandwidth Control
=====================
[ This document only discusses CPU bandwidth control for SCHED_NORMAL.
The SCHED_RT case is covered in Documentation/scheduler/sched-rt-group.txt ]
CFS bandwidth control is a CONFIG_FAIR_GROUP_SCHED extension which allows the
specification of the maximum CPU bandwidth available to a group or hierarchy.
The bandwidth allowed for a group is specified using a quota and period. Within
each given "period" (microseconds), a group is allowed to consume only up to
"quota" microseconds of CPU time. When the CPU bandwidth consumption of a
group exceeds this limit (for that period), the tasks belonging to its
hierarchy will be throttled and are not allowed to run again until the next
period.
A group's unused runtime is globally tracked, being refreshed with quota units
above at each period boundary. As threads consume this bandwidth it is
transferred to cpu-local "silos" on a demand basis. The amount transferred
within each of these updates is tunable and described as the "slice".
Management
----------
Quota and period are managed within the cpu subsystem via cgroupfs.
cpu.cfs_quota_us: the total available run-time within a period (in microseconds)
cpu.cfs_period_us: the length of a period (in microseconds)
cpu.stat: exports throttling statistics [explained further below]
The default values are:
cpu.cfs_period_us=100ms
cpu.cfs_quota=-1
A value of -1 for cpu.cfs_quota_us indicates that the group does not have any
bandwidth restriction in place, such a group is described as an unconstrained
bandwidth group. This represents the traditional work-conserving behavior for
CFS.
Writing any (valid) positive value(s) will enact the specified bandwidth limit.
The minimum quota allowed for the quota or period is 1ms. There is also an
upper bound on the period length of 1s. Additional restrictions exist when
bandwidth limits are used in a hierarchical fashion, these are explained in
more detail below.
Writing any negative value to cpu.cfs_quota_us will remove the bandwidth limit
and return the group to an unconstrained state once more.
Any updates to a group's bandwidth specification will result in it becoming
unthrottled if it is in a constrained state.
System wide settings
--------------------
For efficiency run-time is transferred between the global pool and CPU local
"silos" in a batch fashion. This greatly reduces global accounting pressure
on large systems. The amount transferred each time such an update is required
is described as the "slice".
This is tunable via procfs:
/proc/sys/kernel/sched_cfs_bandwidth_slice_us (default=5ms)
Larger slice values will reduce transfer overheads, while smaller values allow
for more fine-grained consumption.
Statistics
----------
A group's bandwidth statistics are exported via 3 fields in cpu.stat.
cpu.stat:
- nr_periods: Number of enforcement intervals that have elapsed.
- nr_throttled: Number of times the group has been throttled/limited.
- throttled_time: The total time duration (in nanoseconds) for which entities
of the group have been throttled.
This interface is read-only.
Hierarchical considerations
---------------------------
The interface enforces that an individual entity's bandwidth is always
attainable, that is: max(c_i) <= C. However, over-subscription in the
aggregate case is explicitly allowed to enable work-conserving semantics
within a hierarchy.
e.g. \Sum (c_i) may exceed C
[ Where C is the parent's bandwidth, and c_i its children ]
There are two ways in which a group may become throttled:
a. it fully consumes its own quota within a period
b. a parent's quota is fully consumed within its period
In case b) above, even though the child may have runtime remaining it will not
be allowed to until the parent's runtime is refreshed.
Examples
--------
1. Limit a group to 1 CPU worth of runtime.
If period is 250ms and quota is also 250ms, the group will get
1 CPU worth of runtime every 250ms.
# echo 250000 > cpu.cfs_quota_us /* quota = 250ms */
# echo 250000 > cpu.cfs_period_us /* period = 250ms */
2. Limit a group to 2 CPUs worth of runtime on a multi-CPU machine.
With 500ms period and 1000ms quota, the group can get 2 CPUs worth of
runtime every 500ms.
# echo 1000000 > cpu.cfs_quota_us /* quota = 1000ms */
# echo 500000 > cpu.cfs_period_us /* period = 500ms */
The larger period here allows for increased burst capacity.
3. Limit a group to 20% of 1 CPU.
With 50ms period, 10ms quota will be equivalent to 20% of 1 CPU.
# echo 10000 > cpu.cfs_quota_us /* quota = 10ms */
# echo 50000 > cpu.cfs_period_us /* period = 50ms */
By using a small period here we are ensuring a consistent latency
response at the expense of burst capacity.

2
Documentation/scsi/aic7xxx_old.txt
View File

@ -444,7 +444,7 @@ linux-1.1.x and fairly stable since linux-1.2.x, and are also in FreeBSD
Kernel Compile options
------------------------------
The various kernel compile time options for this driver are now fairly
well documented in the file Documentation/Configure.help. In order to
well documented in the file drivers/scsi/Kconfig. In order to
see this documentation, you need to use one of the advanced configuration
programs (menuconfig and xconfig). If you are using the "make menuconfig"
method of configuring your kernel, then you would simply highlight the

5
Documentation/scsi/scsi_mid_low_api.txt
View File

@ -55,11 +55,6 @@ or in the same directory as the C source code. For example to find a url
about the USB mass storage driver see the
/usr/src/linux/drivers/usb/storage directory.
The Linux kernel source Documentation/DocBook/scsidrivers.tmpl file
refers to this file. With the appropriate DocBook tool-set, this permits
users to generate html, ps and pdf renderings of information within this
file (e.g. the interface functions).
Driver structure
================
Traditionally an LLD for the SCSI subsystem has been at least two files in

3
Documentation/security/keys-trusted-encrypted.txt
View File

@ -156,4 +156,5 @@ Load an encrypted key "evm" from saved blob:
Other uses for trusted and encrypted keys, such as for disk and file encryption
are anticipated. In particular the new format 'ecryptfs' has been defined in
in order to use encrypted keys to mount an eCryptfs filesystem. More details
about the usage can be found in the file 'Documentation/keys-ecryptfs.txt'.
about the usage can be found in the file
'Documentation/security/keys-ecryptfs.txt'.

8
Documentation/serial/serial-rs485.txt
View File

@ -28,6 +28,10 @@
RS485 communications. This data structure is used to set and configure RS485
parameters in the platform data and in ioctls.
The device tree can also provide RS485 boot time parameters (see [2]
for bindings). The driver is in charge of filling this data structure from
the values given by the device tree.
Any driver for devices capable of working both as RS232 and RS485 should
provide at least the following ioctls:
@ -104,6 +108,9 @@
rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
rs485conf.delay_rts_after_send = ...;
/* Set this flag if you want to receive data even whilst sending data */
rs485conf.flags |= SER_RS485_RX_DURING_TX;
if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) {
/* Error handling. See errno. */
}
@ -118,3 +125,4 @@
5. REFERENCES
[1] include/linux/serial.h
[2] Documentation/devicetree/bindings/serial/rs485.txt

3
Documentation/sound/oss/PAS16
View File

@ -60,8 +60,7 @@ With PAS16 you can use two audio device files at the same time. /dev/dsp (and
The new stuff for 2.3.99 and later
============================================================================
The following configuration options from Documentation/Configure.help
are relevant to configuring the PAS16:
The following configuration options are relevant to configuring the PAS16:
Sound card support
CONFIG_SOUND

4
Documentation/spi/pxa2xx
View File

@ -2,7 +2,7 @@ PXA2xx SPI on SSP driver HOWTO
===================================================
This a mini howto on the pxa2xx_spi driver. The driver turns a PXA2xx
synchronous serial port into a SPI master controller
(see Documentation/spi/spi_summary). The driver has the following features
(see Documentation/spi/spi-summary). The driver has the following features
- Support for any PXA2xx SSP
- SSP PIO and SSP DMA data transfers.
@ -85,7 +85,7 @@ Declaring Slave Devices
-----------------------
Typically each SPI slave (chip) is defined in the arch/.../mach-*/board-*.c
using the "spi_board_info" structure found in "linux/spi/spi.h". See
"Documentation/spi/spi_summary" for additional information.
"Documentation/spi/spi-summary" for additional information.
Each slave device attached to the PXA must provide slave specific configuration
information via the structure "pxa2xx_spi_chip" found in

14
Documentation/stable_kernel_rules.txt
View File

@ -24,10 +24,10 @@ Rules on what kind of patches are accepted, and which ones are not, into the
Procedure for submitting patches to the -stable tree:
- Send the patch, after verifying that it follows the above rules, to
stable@kernel.org. You must note the upstream commit ID in the changelog
of your submission.
stable@vger.kernel.org. You must note the upstream commit ID in the
changelog of your submission.
- To have the patch automatically included in the stable tree, add the tag
Cc: stable@kernel.org
Cc: stable@vger.kernel.org
in the sign-off area. Once the patch is merged it will be applied to
the stable tree without anything else needing to be done by the author
or subsystem maintainer.
@ -35,10 +35,10 @@ Procedure for submitting patches to the -stable tree:
cherry-picked than this can be specified in the following format in
the sign-off area:
Cc: <stable@kernel.org> # .32.x: a1f84a3: sched: Check for idle
Cc: <stable@kernel.org> # .32.x: 1b9508f: sched: Rate-limit newidle
Cc: <stable@kernel.org> # .32.x: fd21073: sched: Fix affinity logic
Cc: <stable@kernel.org> # .32.x
Cc: <stable@vger.kernel.org> # .32.x: a1f84a3: sched: Check for idle
Cc: <stable@vger.kernel.org> # .32.x: 1b9508f: sched: Rate-limit newidle
Cc: <stable@vger.kernel.org> # .32.x: fd21073: sched: Fix affinity logic
Cc: <stable@vger.kernel.org> # .32.x
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The tag sequence has the meaning of:

2
Documentation/timers/highres.txt
View File

@ -30,7 +30,7 @@ hrtimer base infrastructure
---------------------------
The hrtimer base infrastructure was merged into the 2.6.16 kernel. Details of
the base implementation are covered in Documentation/hrtimers/hrtimer.txt. See
the base implementation are covered in Documentation/timers/hrtimers.txt. See
also figure #2 (OLS slides p. 15)
The main differences to the timer wheel, which holds the armed timer_list type

6
Documentation/usb/dma.txt
View File

@ -7,7 +7,7 @@ API OVERVIEW
The big picture is that USB drivers can continue to ignore most DMA issues,
though they still must provide DMA-ready buffers (see
Documentation/PCI/PCI-DMA-mapping.txt). That's how they've worked through
Documentation/DMA-API-HOWTO.txt). That's how they've worked through
the 2.4 (and earlier) kernels.
OR: they can now be DMA-aware.
@ -57,7 +57,7 @@ and effects like cache-trashing can impose subtle penalties.
force a consistent memory access ordering by using memory barriers. It's
not using a streaming DMA mapping, so it's good for small transfers on
systems where the I/O would otherwise thrash an IOMMU mapping. (See
Documentation/PCI/PCI-DMA-mapping.txt for definitions of "coherent" and
Documentation/DMA-API-HOWTO.txt for definitions of "coherent" and
"streaming" DMA mappings.)
Asking for 1/Nth of a page (as well as asking for N pages) is reasonably
@ -88,7 +88,7 @@ WORKING WITH EXISTING BUFFERS
Existing buffers aren't usable for DMA without first being mapped into the
DMA address space of the device. However, most buffers passed to your
driver can safely be used with such DMA mapping. (See the first section
of Documentation/PCI/PCI-DMA-mapping.txt, titled "What memory is DMA-able?")
of Documentation/DMA-API-HOWTO.txt, titled "What memory is DMA-able?")
- When you're using scatterlists, you can map everything at once. On some
systems, this kicks in an IOMMU and turns the scatterlists into single

45
Documentation/usb/dwc3.txt Normal file
View File

@ -0,0 +1,45 @@
TODO
~~~~~~
Please pick something while reading :)
- Convert interrupt handler to per-ep-thread-irq
As it turns out some DWC3-commands ~1ms to complete. Currently we spin
until the command completes which is bad.
Implementation idea:
- dwc core implements a demultiplexing irq chip for interrupts per
endpoint. The interrupt numbers are allocated during probe and belong
to the device. If MSI provides per-endpoint interrupt this dummy
interrupt chip can be replaced with "real" interrupts.
- interrupts are requested / allocated on usb_ep_enable() and removed on
usb_ep_disable(). Worst case are 32 interrupts, the lower limit is two
for ep0/1.
- dwc3_send_gadget_ep_cmd() will sleep in wait_for_completion_timeout()
until the command completes.
- the interrupt handler is split into the following pieces:
- primary handler of the device
goes through every event and calls generic_handle_irq() for event
it. On return from generic_handle_irq() in acknowledges the event
counter so interrupt goes away (eventually).
- threaded handler of the device
none
- primary handler of the EP-interrupt
reads the event and tries to process it. Everything that requries
sleeping is handed over to the Thread. The event is saved in an
per-endpoint data-structure.
We probably have to pay attention not to process events once we
handed something to thread so we don't process event X prio Y
where X > Y.
- threaded handler of the EP-interrupt
handles the remaining EP work which might sleep such as waiting
for command completion.
Latency:
There should be no increase in latency since the interrupt-thread has a
high priority and will be run before an average task in user land
(except the user changed priorities).

34
Documentation/usb/power-management.txt
View File

@ -439,10 +439,10 @@ cause autosuspends to fail with -EBUSY if the driver needs to use the
device.
External suspend calls should never be allowed to fail in this way,
only autosuspend calls. The driver can tell them apart by checking
the PM_EVENT_AUTO bit in the message.event argument to the suspend
method; this bit will be set for internal PM events (autosuspend) and
clear for external PM events.
only autosuspend calls. The driver can tell them apart by applying
the PMSG_IS_AUTO() macro to the message argument to the suspend
method; it will return True for internal PM events (autosuspend) and
False for external PM events.
Mutual exclusion
@ -487,3 +487,29 @@ succeed, it may still remain active and thus cause the system to
resume as soon as the system suspend is complete. Or the remote
wakeup may fail and get lost. Which outcome occurs depends on timing
and on the hardware and firmware design.
xHCI hardware link PM
---------------------
xHCI host controller provides hardware link power management to usb2.0
(xHCI 1.0 feature) and usb3.0 devices which support link PM. By
enabling hardware LPM, the host can automatically put the device into
lower power state(L1 for usb2.0 devices, or U1/U2 for usb3.0 devices),
which state device can enter and resume very quickly.
The user interface for controlling USB2 hardware LPM is located in the
power/ subdirectory of each USB device's sysfs directory, that is, in
/sys/bus/usb/devices/.../power/ where "..." is the device's ID. The
relevant attribute files is usb2_hardware_lpm.
power/usb2_hardware_lpm
When a USB2 device which support LPM is plugged to a
xHCI host root hub which support software LPM, the
host will run a software LPM test for it; if the device
enters L1 state and resume successfully and the host
supports USB2 hardware LPM, this file will show up and
driver will enable hardware LPM for the device. You
can write y/Y/1 or n/N/0 to the file to enable/disable
USB2 hardware LPM manually. This is for test purpose mainly.

2
Documentation/virtual/lguest/lguest.c
View File

@ -436,7 +436,7 @@ static unsigned long load_bzimage(int fd)
/*
* Go back to the start of the file and read the header. It should be
* a Linux boot header (see Documentation/x86/i386/boot.txt)
* a Linux boot header (see Documentation/x86/boot.txt)
*/
lseek(fd, 0, SEEK_SET);
read(fd, &boot, sizeof(boot));

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