Hi,
John Youn <John.Youn@xxxxxxxxxxxx> writes:
> On 10/12/2015 12:25 PM, Felipe Balbi wrote:
>> This reverts commit 70f3a9caa11665e9f9aace581d85d8483716a4c8.
>>
>> That commit was causing a lockdep splat with g_ether and that
>> was interfering with proper functionality.
>>
>> Signed-off-by: Felipe Balbi <balbi@xxxxxx>
>> ---
>> drivers/usb/dwc3/gadget.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>> index cca806e09e5b..81bfb9ad1e2e 100644
>> --- a/drivers/usb/dwc3/gadget.c
>> +++ b/drivers/usb/dwc3/gadget.c
>> @@ -2642,15 +2642,16 @@ static irqreturn_t dwc3_process_event_buf(struct dwc3 *dwc, u32 buf)
>> static irqreturn_t dwc3_thread_interrupt(int irq, void *_dwc)
>> {
>> struct dwc3 *dwc = _dwc;
>> + unsigned long flags;
>> irqreturn_t ret = IRQ_NONE;
>> int i;
>>
>> - spin_lock(&dwc->lock);
>> + spin_lock_irqsave(&dwc->lock, flags);
>>
>> for (i = 0; i < dwc->num_event_buffers; i++)
>> ret |= dwc3_process_event_buf(dwc, i);
>>
>> - spin_unlock(&dwc->lock);
>> + spin_unlock_irqrestore(&dwc->lock, flags);
>>
>> return ret;
>> }
>>
>
> Hi Felipe,
>
> This seems related to a problem we've been tracking down the past
> few days. This commit, 70f3a9ca, and commit a66c275b both cause
> regression on one of our systems running mass-storage gadget.
I can't see how a66c275b could cause any issues. Our top half runs in
hardirq context with IRQs disabled; this has been discussed several times.
> a66c275b was introduced first, and until 70f3a9ca is introduced
> if we revert just that, it works fine. 70f3a9ca causes similar
> issues. So we must revert both in order to get back to a working
> state.
>
> Failure happens during enumeration and appears to be a race
> condition in the event handling.
>
> Attached are driver logs/traces for the failure with a66c275b.
All I see is a bunch of Start Transfer commands which failed. That's
odd. Which version of the core are you using ? Dwc3 or dwc31 ?
--
balbi
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