[PATCH] usb: xhci: reset endpoint on USB stall

[Stefan Agner]

Bin Meng,

On 2021-09-27 17:14, Marek Vasut wrote:
> On 9/27/21 2:42 PM, Stefan Agner wrote:
>> There are devices which cause a USB stall when trying to read strings.
>> Specifically Arduino Mega R3 stalls when trying to read the product
>> string.
>>
>> The stall currently remains unhandled, and subsequent retries submit new
>> transfers on a stopped endpoint which ultimately cause a crash in
>> abort_td():
>> WARN halted endpoint, queueing URB anyway.
>> XHCI control transfer timed out, aborting...
>> Unexpected XHCI event TRB, skipping... (3affe040 00000000 13000000 02008401)
>> BUG at drivers/usb/host/xhci-ring.c:505/abort_td()!
>> BUG!
>> resetting ...
>>
>> Linux seems to be able to recover from the stall by issuing a
>> TRB_RESET_EP command.
>>
>> Introduce reset_ep() which issues a TRB_RESET_EP followed by setting the
>> transfer ring dequeue pointer via TRB_SET_DEQ. This allows to properly
>> recover from a USB stall error and continue communicating with the USB
>> device.
>>
>> Signed-off-by: Stefan Agner <stefan at agner.ch>
> 
> I hope to get AB/RB from Bin here, then it can go into this release I think.

Any chance you could have a look at this to get it into this release :)

--
Stefan