forked from Minki/linux
0714a57c68
When an URB is cancelled, the xHCI driver issues a Stop Endpoint command so that it can manipulate the ring and remove the transfer. The xHC hardware then places a transfer event with the completion code "Stopped" or "Stopped Invalid" to let the driver know what TD it was in the middle of processing. This TD and TRB is stored in ep->stopped_td and ep->stopped_trb. These pointers are also used in handling stalled endpoints. By design, the Stop Endpoint command can race with URB completion. By the time the Stop Endpoint command is handled, the URBs to be cancelled may have been given back to the driver. Unfortunately, the stopped_td and stopped_trb pointers were not getting cleared in this case. The USB core unconditionally tries to reset the toggle bits on any endpoints when a new alternate interface setting is installed. When the xHCI driver saw that ep->stopped_td was still set from the Stop Endpoint command, xhci_reset_endpoint assumed the endpoint was actually stalled, and attempted to clean up the endpoint rings. This would manifest itself in a failed Reset Endpoint command and failed Set TR dequeue Pointer command after a successful Configure Endpoint command. It may have also been causing driver oops when the stopped_td was accessed. This patch should be backported to stable kernels since 2.6.31. Before 2.6.33, stopped_td was found in the xhci_endpoint_ring, not the xhci_virt_ep. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> |
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| atm | ||
| c67x00 | ||
| class | ||
| core | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| otg | ||
| renesas_usbhs | ||
| serial | ||
| storage | ||
| wusbcore | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| usb-skeleton.c | ||
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.