Re: [PATCH v4 2/6] usb: dwc3: gadget: cancel requests instead of release after missed isoc

[Michael Grzeschik <mgr@pengutronix.de>]

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Hi Thinh,

On Mon, Oct 24, 2022 at 10:47:53PM +0000, Thinh Nguyen wrote:
>On Sat, Oct 22, 2022, Jeff Vanhoof wrote:
>> Hi Greg,
>>
>> On Sat, Oct 22, 2022 at 01:31:24PM +0200, Greg Kroah-Hartman wrote:
>> > On Tue, Oct 18, 2022 at 04:50:38PM -0500, Dan Vacura wrote:
>> > > From: Jeff Vanhoof <qjv001@motorola.com>
>> > >
>> > > arm-smmu related crashes seen after a Missed ISOC interrupt when
>> > > no_interrupt=1 is used. This can happen if the hardware is still using
>> > > the data associated with a TRB after the usb_request's ->complete call
>> > > has been made.  Instead of immediately releasing a request when a Missed
>> > > ISOC interrupt has occurred, this change will add logic to cancel the
>> > > request instead where it will eventually be released when the
>> > > END_TRANSFER command has completed. This logic is similar to some of the
>> > > cleanup done in dwc3_gadget_ep_dequeue.
>> > >
>> > > Fixes: 6d8a019614f3 ("usb: dwc3: gadget: check for Missed Isoc from event status")
>> > > Cc: <stable@vger.kernel.org>
>> > > Signed-off-by: Jeff Vanhoof <qjv001@motorola.com>
>> > > Co-developed-by: Dan Vacura <w36195@motorola.com>
>> > > Signed-off-by: Dan Vacura <w36195@motorola.com>
>> > > ---
>> > > V1 -> V3:
>> > > - no change, new patch in series
>> > > V3 -> V4:
>> > > - no change
>> >
>> > I need an ack from the dwc3 maintainer before I can take this one.
>> >
>> > thanks,
>> >
>> > greg k-h
>>
>> Thinh has rejected this version of the patch. He has provided an alternative
>> implementation which has been testing well for us so far. Either Thinh or Dan
>> will formalize this patch within the next few days.
>> The latest proposed changes are:
>>
>> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
>> index dfaf9ac24c4f..50287437d6de 100644
>> --- a/drivers/usb/dwc3/gadget.c
>> +++ b/drivers/usb/dwc3/gadget.c
>> @@ -3195,6 +3195,9 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep,
>>         if (event->status & DEPEVT_STATUS_SHORT && !chain)
>>                 return 1;
>>
>> +       if (DWC3_TRB_SIZE_TRBSTS(trb->size) == DWC3_TRBSTS_MISSED_ISOC && !chain)
>> +               return 1;
>> +
>>         if ((trb->ctrl & DWC3_TRB_CTRL_IOC) ||
>>             (trb->ctrl & DWC3_TRB_CTRL_LST))
>>                 return 1;
>> @@ -3211,6 +3214,7 @@ static int dwc3_gadget_ep_reclaim_trb_sg(struct dwc3_ep *dep,
>>         struct scatterlist *s;
>>         unsigned int num_queued = req->num_queued_sgs;
>>         unsigned int i;
>> +       bool missed_isoc = false;
>>         int ret = 0;
>>
>>         for_each_sg(sg, s, num_queued, i) {
>> @@ -3219,12 +3223,18 @@ static int dwc3_gadget_ep_reclaim_trb_sg(struct dwc3_ep *dep,
>>                 req->sg = sg_next(s);
>>                 req->num_queued_sgs--;
>>
>> +               if (DWC3_TRB_SIZE_TRBSTS(trb->size) == DWC3_TRBSTS_MISSED_ISOC)
>> +                       missed_isoc = true;
>> +
>>                 ret = dwc3_gadget_ep_reclaim_completed_trb(dep, req,
>>                                 trb, event, status, true);
>>                 if (ret)
>>                         break;
>>         }
>>
>> +       if (missed_isoc)
>> +               ret = 1;
>> +
>>         return ret;
>>  }
>>
>>
>
>That's just a debug patch. I'll send out proper fix patches.

Ping!

While digging out this thread, I did not find any followup patch
for this suggestion. Did it hit the mailinglist anywhere?

If not, will you send one?

Regards,
Michael

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