On Tue, Oct 25, 2022, Jeff Vanhoof wrote:
> Hi Thinh,
>
> On Mon, Oct 24, 2022 at 11:51:50PM -0500, Jeff Vanhoof wrote:
> > On Mon, Oct 24, 2022 at 06:28:04PM -0700, Thinh Nguyen wrote:
> > > The gadget driver may have a certain expectation of how the request
> > > completion flow should be from to its configuration. Make sure the
> > > controller driver respect that. That is, don't set IMI (Interrupt on
> > > Missed Isoc) when usb_request->no_interrupt is set.
> > >
> > > Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > Signed-off-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
> > > ---
> > > Changes in v2:
> > > - None
> > >
> > > drivers/usb/dwc3/gadget.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > > index 230b3c660054..702bdf42ad2f 100644
> > > --- a/drivers/usb/dwc3/gadget.c
> > > +++ b/drivers/usb/dwc3/gadget.c
> > > @@ -1292,8 +1292,8 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
> > > trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS;
> > > }
> > >
> > > - /* always enable Interrupt on Missed ISOC */
> > > - trb->ctrl |= DWC3_TRB_CTRL_ISP_IMI;
> > > + if (!req->request.no_interrupt)
> > > + trb->ctrl |= DWC3_TRB_CTRL_ISP_IMI;
> > > break;
> > >
> > > case USB_ENDPOINT_XFER_BULK:
> > > --
> > > 2.28.0
> > >
> >
> <snip>
>
> For scatter gather, shouldn't the IMI bit be set only for the TRB associated
> to the last item in the sg list? Do we need to do something similar to what
> that was done for IOC in this area?
>
> For ex.:
> + if ((!req->request.no_interrupt && !chain) || must_interrupt)
> + trb->ctrl |= DWC3_TRB_CTRL_ISP_IMI;
>
> BTW, Dan indicated that this seems to help resolve the crash mentioned in
> [PATCH v2 1/2] of this chain.
>
Actually, that's correct. Just ignore the "must_interrupt" setting. The
programming guide actually noted to set the IMI for the last TRB of the
chain also.
I'll send a fix to this.
Thanks,
Thinh
