This patch implements xHCI bus suspend/resume function hook.
In the patch it goes through all the ports and suspend/resume
the ports if needed.
If any port is in remote wakeup, abort bus suspend as what ehci/ohci do.
Signed-off-by: Libin Yang <libin.yang@amd.com>
Signed-off-by: Crane Cai <crane.cai@amd.com>
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit implements port remote wakeup.
When a port is in U3 state and resume signaling is detected from a device,
the port transitions to the Resume state, and the xHC generates a Port Status
Change Event.
For USB3 port, software write a '0' to the PLS field to complete the resume
signaling. For USB2 port, the resume should be signaling for at least 20ms,
irq handler set a timer for port remote wakeup, and then finishes process in
hub_control GetPortStatus.
Some codes are borrowed from EHCI code.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add software trigger USB device suspend resume function hook.
Do port suspend & resume in terms of xHCI spec.
Port Suspend:
Stop all endpoints via Stop Endpoint Command with Suspend (SP) flag set.
Place individual ports into suspend mode by writing '3' for Port Link State
(PLS) field into PORTSC register. This can only be done when the port is in
Enabled state. When writing, the Port Link State Write Strobe (LWS) bit shall
be set to '1'.
Allocate an xhci_command and stash it in xhci_virt_device to wait completion for
the last Stop Endpoint Command. Use the Suspend bit in TRB to indicate the Stop
Endpoint Command is for port suspend. Based on Sarah's suggestion.
Port Resume:
Write '0' in PLS field, device will transition to running state.
Ring an endpoints' doorbell to restart it.
Ref: USB device remote wake need another patch to implement. For details of
how USB subsystem do power management, please see:
Documentation/usb/power-management.txt
Signed-off-by: Crane Cai <crane.cai@amd.com>
Signed-off-by: Libin Yang <libin.yang@amd.com>
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When the system suspends and a host controller's power is lost, the USB
core attempts to revive any USB devices that had the persist_enabled flag
set. For non-SuperSpeed devices, it will disable the port, and then set
the udev->reset_resume flag. This will cause the USB core to reset the
device, verify the device descriptors to make sure it's the same device,
and re-install any non-default configurations or alternate interface
settings.
However, we can't disable SuperSpeed root hub ports because that turns off
SuperSpeed terminations, which will inhibit any devices connecting at USB
3.0 speeds. (Plus external hubs don't allow SuperSpeed ports to be
disabled.)
Because of this logic in hub_activate():
/* We can forget about a "removed" device when there's a
* physical disconnect or the connect status changes.
*/
if (!(portstatus & USB_PORT_STAT_CONNECTION) ||
(portchange & USB_PORT_STAT_C_CONNECTION))
clear_bit(port1, hub->removed_bits);
if (!udev || udev->state == USB_STATE_NOTATTACHED) {
/* Tell khubd to disconnect the device or
* check for a new connection
*/
if (udev || (portstatus & USB_PORT_STAT_CONNECTION))
set_bit(port1, hub->change_bits);
} else if (portstatus & USB_PORT_STAT_ENABLE) {
/* The power session apparently survived the resume.
* If there was an overcurrent or suspend change
* (i.e., remote wakeup request), have khubd
* take care of it.
*/
if (portchange)
set_bit(port1, hub->change_bits);
} else if (udev->persist_enabled) {
udev->reset_resume = 1;
set_bit(port1, hub->change_bits);
} else {
/* The power session is gone; tell khubd */
usb_set_device_state(udev, USB_STATE_NOTATTACHED);
set_bit(port1, hub->change_bits);
}
a SuperSpeed device after a resume with a loss of power will never get the
reset_resume flag set. Instead the core will assume the power session
survived and that the device still has the same address, configuration,
and alternate interface settings. The xHCI host controller will have no
knowledge of the device (since all xhci_virt_devices were destroyed when
power loss was discovered, and xhci_discover_or_reset_device() has not
been called), and all URBs to the device will fail.
If the device driver responds by resetting the device, everything will
continue smoothly. However, if lsusb is used before the device driver
resets the device (or there is no driver), then all lsusb descriptor
fetches will fail.
The quick fix is to pretend the port is disabled in hub_activate(), by
clearing the local variable. But I'm not sure what other parts of the hub
driver need to be changed because they have assumptions about when ports
will be disabled.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
xHCI driver uses hardware assigned device address. This may cause device
address conflict in certain cases.
Use kernel assigned address for devices under xHCI. Store the xHC assigned
address locally in xHCI driver.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Rename xhci_reset_device() to xhci_discover_or_reset_device().
If xhci_discover_or_reset_device() is called to reset a device which does
not exist or does not match the udev, it calls xhci_alloc_dev() to
re-allocate the device.
This would prevent the reset device failure, possibly due to the xHC restore
error during S3/S4 resume.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add a pointer to udev in struct xhci_virt_device. When allocate a new
virt_device, make the pointer point to the corresponding udev.
Modify xhci_check_args(), check if virt_dev->udev matches the target udev,
to make sure command is issued to the right device.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some functions changed by 1c98347e61.
However, There was a change mistake of the function (outsw).
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
CC: Paul Mundt <lethal@linux-sh.org>
Cc: stable <stable@kernel.org> [.35 & .36]
Acked-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Extend id's table to have ulpi phy names in it.
Report if the known phy is found.
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Improve ulpi phy detection by utilizing the "scratch" register.
Allow unknown ulpi phy work without the need to hard-code the id.
Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
OPN2001 expects write operations to arrive as a vendor-specific command
through the control pipe (instead of using a separate bulk-out pipe).
Signed-off-by: Alon Ziv <alon-git@nolaviz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The bulk-read callback had two bugs:
a) The bulk-in packet's leading two zeros were returned (and the two last
bytes truncated)
b) The wrong URB was transmitted for the second (and later) read requests,
causing further reads to return the entire packet (including leading
zeros)
Signed-off-by: Alon Ziv <alon-git@nolaviz.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
No need to set latency timeout at every open.
This also fixes an issue with the read latency being as high as 250ms
(instead of 1ms) for the first read after port probe.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If the iowarrior devices in this case statement support more than 8 bytes
per report, it is possible to write past the end of a kernel heap allocation.
This will probably never be possible, but change the allocation to be more
defensive anyway.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix regression introduced by commit
214916f2ec (USB: visor: reimplement using
generic framework) which broke initialisation of UX50/TH55 devices that
used re-mapped bulk-out endpoint addresses.
Reported-by: Robert Gadsdon <rgadsdon@bayarea.net>
Tested-by: Robert Gadsdon <rgadsdon@bayarea.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch for FTDI USB serial driver ads new VID/PIDs used on various
devices manufactured by Papouch (http://www.papouch.com). These devices
have their own VID/PID, although they're using standard FTDI chip. In
ftdi_sio.c, I also made small cleanup to have declarations for all
Papouch devices together.
Signed-off-by: Daniel Suchy <danny@danysek.cz>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Adding SuperSpeed usb definitions as defined by ch9 of the USB3.0 spec.
This patch is a preparation for adding SuperSpeed support to the gadget
framework.
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit changes storage_common.h, file_storage.c and
f_mass_storage.c to use definitions of SCSI commands from
scsi/scsi.h file instead of redefining the commands in
storage_common.c.
scsi/scsi.h header file was missing READ_FORMAT_CAPACITIES and
READ_HEADER so this commit also add those to the header.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
For all modules, change <module>-objs to <module>-y; remove
if-statements and replace with lists using the kbuild idiom; move
flags to the top of the file; and fix alignment while trying to
maintain the original scheme in each file.
None of the dependencies are modified.
Signed-off-by: matt mooney <mfm@muteddisk.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In function dummy_udc_probe()
call put_device() when device_register() fails.
also usb_get_hcd() put before device_register() after review comment
from Alan Stern.
Signed-off-by: Rahul Ruikar <rahul.ruikar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
At otg device mode, the otg host resume should do no-op during
system resume, otherwise, the otg device will be treated as a
host for enumeration.
So, the otg host driver returns -ESHUTDOWN if it detects the
current usb mode is device mode. The host driver has to return
-ESHUTDOWN, otherwise, the usb_hc_died will be called.
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some Rockbox based mp4 players will crash when ever they see a
read_capacity_16 scsi command. So add a new US_FL which tells the scsi sd
driver to not issue any read_capacity_16 scsi commands.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
I seem to have a knack for digging up buggy usb devices which don't work
with Linux, and I'm crazy enough to try to make them work. So this time a
friend of mine asked me to get an mp4 player (an mp3 player which can play
videos on a small screen) to work with Linux.
It is based on the well known rockbox chipset for which we already have an
unusual devs entries to work around some of its bugs. But this model
comes with an additional twist.
This model chokes on read_capacity_16 calls. Now normally we don't make
those calls, but this model comes with an sdcard slot and when there is no
card in there (and shipped from the factory there is none), it reports a
size of 0. However this time the programmers actually got the
read_capacity_10 response right! So they substract one from the size as
stored internally in the mp3 player before reporting it back, resulting in
an answer of ... 0xffffffff sectors, causing sd.c to try a
read_capacity_16, on which the device crashes.
This patch adds a flag to scsi_device to indicate that a a device cannot
handle read_capacity_16, and when this flag is set if a device reports an
lba of 0xffffffff as answer to a read_capacity_10, assumes it tries to
report a size of 0.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Appotech ax3003 (the larger brother of the ax203) based devices are even
more buggy then the ax203. They will go of into lala land when ever they
see a READ_DISC_INFO scsi command. So add a new US_FL which tells the
scsi sr driver to not issue any READ_DISC_INFO scsi commands.
[akpm@linux-foundation.org: fix build]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some USB devices emulate a usb-mass-storage attached (scsi) cdrom device,
usually this fake cdrom contains the windows software for the device.
While working on supporting Appotech ax3003 based photoframes, which do
this I discovered that they will go of into lala land when ever they see a
READ_DISC_INFO scsi command.
Thus this patch adds a scsi_device flag (which can then be set by the
usb-storage driver through an unsual-devs entry), to indicate this, and
makes the sr driver honor this flag.
I know this sucks, but as discussed on linux-scsi list there is no other
way to make this device work properly.
Looking at usb traces made under windows, windows never sends a
READ_DISC_INFO during normal interactions with a usb cdrom device. So as
this cdrom emulation thingie becomes more common we might see more of this
problem.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This is based on an initial patch by Rahul Ruikar.
The goku_remove() function can be called before device_register() so it
can call device_unregister() improperly. Also if the call to
device_register() fails we need to call put_device().
As I was changing the error handling in goku_probe(), I noticed that
the label was "done" but actually if the function succeeds we return
earlier. I renamed the error path to "err" instead of "done."
Reported-by: Rahul Ruikar <rahul.ruikar@gmail.com>
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The hardware can only do DMA to 4 byte aligned addresses.
When this requirement is not met use PIO or a bounce buffer.
PIO is used when the buffer is small enough to directly
use the hardware data memory (2*maxpacket).
A bounce buffer is used for larger transfers.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Split unmap_urb_for_dma() to allow just the setup buffer
to be unmapped. This allows HCDs to use PIO for the setup
buffer if it is not suitable for DMA.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Release the hardware resources and reset the internal HCD state
associated with an isochronous endpoint when the last URB queued
for it completes.
Previously this was only done in then endpoint_disable() method
causing usbtest 15 and 16 to hang when run twice in succession
without a disconnect.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We already have fields describing the hardware data memory
(dmem_size and dmem_offset) in the HCD private data,
use them rather than the rather obscure read from the
hardware descriptor.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove a local variable left over from some debugging code.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Check the data length of isochronous transfers is
as expected.
With this test #16 will now fail if the device side
sends no data.
Signed-off-by: Martin Fuzzey <mfuzzey@gmail.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1430) fixes a bug in usbcore. When a device
configuration change occurs or a device is removed, the endpoints for
the old config should be completely disabled. However it turns out
they aren't; this is because usb_unbind_interface() calls
usb_enable_interface() or usb_set_interface() to put interfaces back
in altsetting 0, which re-enables the interfaces' endpoints.
As a result, when a device goes through a config change or is
unconfigured, the ep_in[] and ep_out[] arrays may be left holding old
pointers to usb_host_endpoint structures. If the device is
deauthorized these structures get freed, and the stale pointers cause
errors when the the device is eventually unplugged.
The solution is to disable the endpoints after unbinding the
interfaces instead of before. This isn't as large a change as it
sounds, since usb_unbind_interface() disables all the interface's
endpoints anyway before calling the driver's disconnect routine,
unless the driver claims to support "soft" unbind.
This fixes Bugzilla #19192. Thanks to "Tom" Lei Ming for diagnosing
the underlying cause of the problem.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Carsten Sommer <carsten_sommer@ymail.com>
CC: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
It is safer to cancel pending requests before free dTD and dQH when
controller enters suspend state.
Signed-off-by: Philippe Skowronski <philippe.skowronski@intel.com>
Signed-off-by: Hao Wu <hao.wu@intel.com>
[Switch to spin_lock_irq as suggested by Alan Stern]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch fixing the problem with large file transfers failing. Swap the read
order to avoid unexpected RX status.
Signed-off-by: Christophe Lebouc <christophex.lebouc@intel.com>
Signed-off-by: Hao Wu <hao.wu@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch adds native scatter-gather support to uhci-hcd.
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Blackfin's musb_platform_exit() forgets to call usb_nop_xceiv_unregister().
While fixing this, also remove the unneeded blank line there.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Since commit 461972d8a4 (musb_core: don't call
musb_platform_exit() twice), unloading the driver module results in a WARNING
"kobject: '(null)' (c73de788): is not initialized, yet kobject_put() is being
called." (or even kernel oops) on e.g. DaVincis, though only in the OTG mode.
There exists dubious and unbalanced put_device() call in musb_free() which
takes place only in the OTG mode. As this commit caused musb_platform_exit()
to be called (and so unregister the NOP transceiver) before this put_device()
call, this function references already freed memory.
On the other hand, all the glue layers miss the otg_put_transceiver() call,
complementary to the otg_get_transceiver() call that they do. So, I think
the solution is to get rid of the strange put_device() call, and instead
call otg_put_transceiver() in the glue layers...
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Extends FSL EHCI platform driver glue layer to support
MPC5121 USB controllers. MPC5121 Rev 2.0 silicon EHCI
registers are in big endian format. The appropriate flags
are set using the information in the platform data structure.
MPC83xx system interface registers are not available on
MPC512x, so the access to these registers is isolated in
MPC512x case. Furthermore the USB controller clocks
must be enabled before 512x register accesses which is
done by providing platform specific init callback.
The MPC512x internal USB PHY doesn't provide supply voltage.
For boards using different power switches allow specifying
DRVVBUS and PWR_FAULT signal polarity of the MPC5121 internal
PHY using "fsl,invert-drvvbus" and "fsl,invert-pwr-fault"
properties in the device tree USB nodes. Adds documentation
for this new device tree bindings.
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Replace FSL USB platform code by simple platform driver for
creation of FSL USB platform devices.
The driver creates platform devices based on the information
from USB nodes in the flat device tree. This is the replacement
for old arch fsl_soc usb code removed by this patch. The driver
uses usual of-style binding, available EHCI-HCD and UDC
drivers can be bound to the created devices. The new of-style
driver additionaly instantiates USB OTG platform device, as the
appropriate USB OTG driver will be added soon.
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The OpenDCC project is developing a new hardware. This patch adds its
PID to the list of known FTDI devices. The PID can be found at
http://www.opendcc.de/elektronik/usb/opendcc_usb.html
Signed-off-by: Rainer Keller <mail@rainerkeller.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add empty functions for get/put transceiver functions too, so that
drivers that optionally use them can call them without worrying that
they might not exist, eliminating ifdefs.
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
commit 633ba7876b96ec339ef685357e2f7c60b5a8ce85 broke
g_file_storage functionality by enabling AUTOCLEAR on
all cases without caring for all gadget drivers.
This patch will only enable AUTOCLEAR if our endpoint's
FIFO was configured with double buffering support. Note
this is not a complete fix, double buffered case still
doesn't work always, but that hasn't been working for
quite some time. Other than reverting the entire commit
and breaking testusb with double buffered case again,
I decided it was better to fix the single buffered case
and spend more time fixing double buffered case properly.
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
