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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On Tue, Sep 19, 2023 at 11:10:55AM +0200, Michael Grzeschik wrote:
>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?

Nevermind, I think I found the hunk in a variated version in this series.

https://lore.kernel.org/linux-usb/cover.1666735451.git.Thinh.Nguyen@synopsys.com/

Michael

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