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

[Thinh Nguyen]

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@xxxxxxxxxxxx>
> > > 
> > > 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@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Jeff Vanhoof <qjv001@xxxxxxxxxxxx>
> > > Co-developed-by: Dan Vacura <w36195@xxxxxxxxxxxx>
> > > Signed-off-by: Dan Vacura <w36195@xxxxxxxxxxxx>
> > > ---
> > > 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.

Thanks,
Thinh