On Wed, Aug 23, 2023 at 02:14:32AM +0000, Thinh Nguyen wrote: > On Sun, Aug 20, 2023, Alan Stern wrote: > > On Sat, Aug 19, 2023 at 12:06:53AM +0000, Thinh Nguyen wrote: > > > On Fri, Aug 18, 2023, Alan Stern wrote: > > > > Actually I agree with you. When a new SETUP packet arrives before the > > > > old control transfer has finished, the UDC driver should cancel all > > > > pending requests and then invoke the ->setup() callback. (I don't think > > > > there is a standard error code for the cancelled requests; net2280 seems > > > > to use -EPROTO whereas dummy-hcd seems to use -EOVERFLOW.) > > > > > > Those are very odd choice of error codes for cancelled request. Even > > > though the gadget side doesn't have very defined error codes, I try to > > > follow the equivalent doc from the host side > > > (driver-api/usb/error-codes.rst), which is -ECONNRESET. > > > > > > Whenever I see -EPROTO, I associate that to a specific host error: > > > transaction error. For -EOVERFLOW, I think of babble errors. > > > > Do you have a suggestion for an error code that all the UDCs should use > > in this situation? -ECONNRESET is currently being used for requests > > that were cancelled by usb_ep_dequeue(). Would -EREMOTEIO be more > > suitable for requests attached to an aborted control transfer? > > > > That works. It would be great if we can document the usb error codes for > gadget side and keep them consistent across UDC drivers. I think there > are only a few common errors: > > * Request aborted > * Request dequeued > * STALL > * Data dropped (isoc only) > > Any other? * Overflow STALL is not a valid status for usb_requests on the gadget side; it applies only on the host side (the host doesn't halt its endpoints). Requests can be aborted for two different reasons: The endpoint is being disabled, either by an config/altsetting change or because of a disconnect The request was for an aborted control transfer Putting this together, I get the following status codes: -ESHUTDOWN Request aborted because ep was disabled -EREMOTEIO Request was for an aborted control transfer -ECONNRESET Request was cancelled by usb_ep_dequeue() -EXDEV Data dropped (isoc only) -EOVERFLOW The host sent more data than the request wanted (will never happen if the request's length is a nonzero multiple of the maxpacket size) This applies only to the .status field of struct usb_request. Calls to usb_ep_queue() may return different error codes. How does that sound? Alan Stern
