Hi Alan, Do you know if there's a chance that any USB drivers (or userspace) would try to clear an endpoint halt when there are active URBs that have not completed on for the endpoint? I ask because in order to handle the case where userspace wants to reset the toggles with a clear halt control transfer, but the endpoint is not actually halted, the xHCI driver needs to wipe out the contents of the endpoint ring and reset the dequeue pointer. (The dequeue pointer alignment for the Configure Endpoint command forces us to set the pointer the top of the ring, or every fourth TRB.) Re-initializing the ring would be bad to do if there were pending URBs that hadn't been canceled before the driver tried to clear the halt. I think it's pretty unlikely for this corner case to occur, but I could potentially see a driver queueing multiple URBs to an endpoint, and clearing the halt that occurred on the first URB, and then expecting the other URB to complete successfully. What would happen under EHCI in this case? Would it be OK to simply return the second URB with a -EPROTO in this case? Or should we save the URBs, re-init the endpoint ring, requeue the URB to the ring, and ring the endpoint doorbell? Sarah Sharp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
