Hi,
Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> writes:
>> Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> writes:
>>> If dwc3 fails to issue START_TRANSFER/UPDATE_TRANSFER command, then we
>>> should properly end an active transfer and give back all the started
>>> requests. However if it's for an isoc endpoint, the failure maybe due to
>>> bus-expiry status. In this case, don't give back the requests and wait
>>> for the next retry.
>>>
>>> Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
>>> Signed-off-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx>
>> could you give some details regarding when does this happen?
>>
>
> So, here are the scenarios in which dwc3_send_gadget_ep_cmd() may return
> a negative errno:
>
> * -EAGAIN: Isoc bus-expiry status
> As you already know, this occurs when we try to schedule isoc too
> late. If we're going to retry the request, don't unmap it.
right
> * -EINVAL: No resource due to issuing START_TRANSFER to an already
> started endpoint
> This happens generally because of SW programming error
Sounds like this should be fixed separately and, probably, we should add
a WARN() so we catch these situations. Have you reproduced this
particular case?
> * -ETIMEDOUT: Polling for CMDACT timed out
> This should not happen unless the controller is dead or in some bad
> state
Understood
--
balbi
Attachment:
signature.asc
Description: PGP signature
