mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-08 11:50:43 +09:00
29b3f4e6bc
commitb63f4053ccupstream. According to xHCI spec section 4.6.1.1 and section 4.6.1.2, after aborting a command on the command ring, xHC will generate a command completion event with its completion code set to Command Ring Stopped at least. If a command is currently executing at the time of aborting a command, xHC also generate a command completion event with its completion code set to Command Abort. When the command ring is stopped, software may remove, add, or rearrage Command Descriptors. To cancel a command, software will initialize a command descriptor for the cancel command, and add it into a cancel_cmd_list of xhci. When the command ring is stopped, software will find the command trbs described by command descriptors in cancel_cmd_list and modify it to No Op command. If software can't find the matched trbs, we can think it had been finished. This patch should be backported to kernels as old as 3.0, that contain the commit7ed603ecf8"xhci: Add an assertion to check for virt_dev=0 bug." That commit papers over a NULL pointer dereference, and this patch fixes the underlying issue that caused the NULL pointer dereference. Note from Sarah: The TRB_TYPE_LINK_LE32 macro is not in the 3.0 stable kernel, so I added it to this patch. Signed-off-by: Elric Fu <elricfu1@gmail.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Tested-by: Miroslav Sabljic <miroslav.sabljic@avl.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.