Messages in this thread | | | From | Baolin Wang <> | Date | Mon, 19 Sep 2016 18:42:45 +0800 | Subject | Re: [PATCH v2 2/2] usb: dwc3: Wait for control tranfer completed when stopping gadget |
| |
Hi Felipe,
On 19 September 2016 at 17:58, Felipe Balbi <balbi@kernel.org> wrote: > > Hi, > > Baolin Wang <baolin.wang@linaro.org> writes: >>>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c >>>> index 1a33308..c9026ce 100644 >>>> --- a/drivers/usb/dwc3/gadget.c >>>> +++ b/drivers/usb/dwc3/gadget.c >>>> @@ -1441,6 +1441,15 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend) >>>> if (pm_runtime_suspended(dwc->dev)) >>>> return 0; >>>> >>>> + /* >>>> + * Per databook, when we want to stop the gadget, if a control transfer >>>> + * is still in process, complete it and get the core into setup phase. >>>> + */ >>>> + if (!is_on && dwc->ep0state != EP0_SETUP_PHASE) { >>>> + reinit_completion(&dwc->ep0_completed); >>> >>> this seems unnecessary to me. Also, why return here so the caller has to >> >> We should re-init the completion due to it will complete control >> transfer many times before we try to stop gadget. > > not sure I get this comment, care to furter explain what you mean?
Sorry for confusing comment. What I mean is it will issue 'complete(&dwc->ep0_completed)' when one control transfer is completed, and it will increase the completion->done when every 'complete()' function is issued.
If there are seveal control transfers are completed (completion->done is not 0 bow) and dwc->ep0state is not in EP0_SETUP_PHASE satus when we want to stop gadget, then we should wait for completion. If we don't call 'reinit_completion(&dwc->ep0_completed)' (it will reset completion->done as 0 ), it will not wait for 500ms in wait_for_completion_timeout() funtion. Hope I make it clear.
> >>> wait? You could just have called wait_for_completion() here straight >>> away: >>> >>> if (!is_on && dwc->ep0state != EP0_SETUP_PHASE) { >>> /* should this be interruptible? */ >>> ret = wait_for_completion_timeout(&dwc->ep0_in_setup, >>> msecs_to_jiffies(500)); >>> if (ret == 0) { >>> dwc3_trace(trace_dwc3_gadget, "RUN/STOP timeout"); >>> return -ETIMEDOUT; >>> } >>> } >>> >>> There's also no need for that "try_again" trickery. We either can halt >>> the controller within 500ms or we cannot. >> >> But this is in atomic context and we can not issue >> wait_for_completion_timeout() in atomic context, then we should just >> return here. > > heh, good point. Missed that :-)
OK:)
-- Baolin.wang Best Regards
| |