Re: dwc3 gadget breaks on system suspend/resume

Roger Quadros
2017-01-31T11:38:01Z

Hi,

On 30/01/17 15:47, Felipe Balbi wrote:
>
> Hi,
>
> Felipe Balbi <balbi-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> writes:
>> Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org> writes:
>>>> Roger Quadros <rogerq-l0cyMroinI0@public.gmane.org> writes:
>>>>>> (hmm, I didn't receive your reply in my intel inbox, only
>>>>>> gmail. Odd. Replying to myself here, but it should be on your reply,
>>>>>> rater).
>>>>>>
>>>>>> Felipe Balbi <balbi-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> writes:
>>>>>>>> The previous commit c499ff71ff2a281366c6ec7a904c547d806cbcd1 is fine.
>>>>>>>
>>>>>>> okay. Then let's try to figure out what's going on. A diff of regdump
>>>>>>> before and after suspend/resume might start to give some clue about
>>>>>>> what's going on. DWC3 tracepoints should help too. Care to get those?
>>>>>>> BTW, is this dwc3 as host or peripheral?
>>>>>>
>>>>>> You don't have any endpoints enabled:
>>>>>>
>>>>>> -DALEPENA = 0x0000000f
>>>>>> +DALEPENA = 0x00000000
>>>>>
>>>>> Thanks for the hints.
>>>>>
>>>>> This problem is because reason dwc3_gadget_run_stop() is timing out
>>>>> during the suspend sequence and so dwc3_disconnect_gadget() and
>>>>> __dwc3_gadget_stop() are not being called.
>>>>
>>>> I see
>>>>
>>>>> dwc3_suspend() does not consider dwc3_gadget_suspend()'s return value
>>>>> and happily continues suspending the machine.
>>>>>
>>>>> If I force dwc3_gadget_run_stop() to return 0 then everything works fine.
>>>>>
>>>>> Any ideas why DWC3_DSTS_DEVCTRLHLT is not getting set?
>>>>
>>>> no idea. It should always get set when run_stop is cleared. Can you
>>>> check if suspending with cable detached has any difference?
>>>
>>> After cable detach, it still timed out the next suspend. But on
>>> subsequent suspends there were no timeouts. (I didn't plug the cable
>>> back at all)
>>>
>>> This behaviour is on dra7. I will test the behaviour on am43x as well.
>>
>> wonder if there's something odd with 2.02a. AM437x is 2.40a IIRC,
>> testing that is, indeed, a good idea.

Tried on am437x which is 2.40a but same timeout problem there as well.

>
> What if your platform just takes longer to halt?
>
> Can you try below?
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index 4db97ecae885..d2e405793b1f 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -1586,7 +1586,7 @@ static int dwc3_gadget_set_selfpowered(struct usb_gadget *g,
> static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
> {
> u32 reg;
> - u32 timeout = 500;
> + u32 timeout = 500000;
>
> if (pm_runtime_suspended(dwc->dev))
> return 0;
>
>

Tried this but it doesn't resolve the issue.