Re: [RFC][PATCH] usb: dwc2: Make sure we disconnect the gadget state on reset

[John Stultz]

On Tue, Oct 25, 2016 at 2:29 PM, John Youn <John.Youn@xxxxxxxxxxxx> wrote:
> On 10/19/2016 11:00 PM, John Stultz wrote:
>> I had seen some odd behavior with HiKey's usb-gadget interface
>> that I finally seemed to have chased down. Basically every other
>> time I pluged in the OTG port, the gadget interface would
>> properly initialize. The other times, I'd get a big WARN_ON
>> in dwc2_hsotg_init_fifo() about the fifo_map not being clear.
>>
>> Ends up If we don't disconnect the gadget state on reset, the
>> fifo-map doesn't get cleared properly, which causes WARN_ON
>> messages and also results in the device not properly being
>> setup as a gadget every other time the OTG port is connected.
>>
>> So this patch adds a call to dwc2_hsotg_disconnect() in the
>> reset path so the state is properly cleared.
>>
>> With it, the gadget interface initializes properly on every
>> plug in.
>>
>> I don't know if this is actually the right fix, but it seems
>> to work well. Feedback would be greatly appreciated!
>>
>> Cc: Wei Xu <xuwei5@xxxxxxxxxxxxx>
>> Cc: Guodong Xu <guodong.xu@xxxxxxxxxx>
>> Cc: Chen Yu <chenyu56@xxxxxxxxxx>
>> Cc: Amit Pundir <amit.pundir@xxxxxxxxxx>
>> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
>> Cc: John Youn <johnyoun@xxxxxxxxxxxx>
>> Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Cc: linux-usb@xxxxxxxxxxxxxxx
>> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
>> ---
>>  drivers/usb/dwc2/gadget.c | 2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
>> index 24fbebc..5505001 100644
>> --- a/drivers/usb/dwc2/gadget.c
>> +++ b/drivers/usb/dwc2/gadget.c
>> @@ -2519,6 +2519,8 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
>>
>>       /* Kill any ep0 requests as controller will be reinitialized */
>>       kill_all_requests(hsotg, hsotg->eps_out[0], -ECONNRESET);
>> +     /* Make sure everything is disconnected */
>> +     dwc2_hsotg_disconnect(hsotg);
>>
>>       if (!is_usb_reset)
>>               if (dwc2_core_reset(hsotg))
>>
>
> Seems fine with our testing.
>
> Acked-by: John Youn <johnyoun@xxxxxxxxxxxx>

Awesome! Thanks so much for the review and testing!

I'm curious, did you happen to have any thoughts or objections on the
"dwc2: Force port resume on switching to device mode" patch
(https://patchwork.kernel.org/patch/9375965/ ) as well?

thanks
-john