Hi Felipe, On 12/22/2014 05:34 PM, Felipe Balbi wrote: > On Mon, Dec 15, 2014 at 11:05:22AM +0100, Robert Baldyga wrote: >> On 12/15/2014 06:13 AM, Peter Chen wrote: >>> On Fri, Dec 12, 2014 at 02:17:28PM +0100, Robert Baldyga wrote: >>>> As usb function drivers assumes that all usb request will be completed >>>> before function unbind call, we should supply such behavior. In some >>>> cases ep_disable() won't kill all request effectively, because some >>>> IN requests can be in running state. In such situation it's possible >>>> to have unbind function called before last request completion, which >>>> can cause problems. >>> >>> Doesn't the function's disable/unbind should call usb_ep_dequeue to make >>> sure the transfer has ended? >> >> USB function drivers like ECM or HID surely doesn't. It looks like >> there's assumption that all requests will be completed by UDC driver. > > that's a bug on those drivers :-) So we can't make assumptions that requests will be completed in ep_disable()? > >> Function ep_disable() should complete requests in hardware driver, but >> at least in DWC2 driver not all requests are completed at this stage > > and that's a bug on dwc2 :-) I have already found that out. Another UDC drivers simply kill all request without waiting for currently running, so I did the same in DWC2. Here is my patch: http://www.spinics.net/lists/linux-usb/msg118698.html > >> (request which are in hardware FIFO are omitted to give them chance to >> be transferred). Those requests are forced to complete in udc_stop() > > that's wrong, we're disabling the endpoint anyway. Either dwc2 needs to > wait_for_completion() or forcibly cancel the request. The bottom line is > that control should not exit ep_disable() until all requests have been > quiesced. So that's not bug in function drivers. They make correct assumption, because they expect that requests will be completed in ep_disable(). > >> function, and that's why it's needed to be called before unbind. >> >>> >>> .udc_stop may stop the controller, and .unbind may still visit hardware. >> >> Hmm, indeed it can be problem. > > yes, it will be :-) > Thanks, Robert Baldyga -- 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
