On Tue, Jul 23, 2019 at 1:27 PM John Stultz <john.stultz@xxxxxxxxxx> wrote: > > From: Anurag Kumar Vulisha <anurag.kumar.vulisha@xxxxxxxxxx> > > The present code in dwc3_gadget_ep_reclaim_completed_trb() will check > for IOC/LST bit in the event->status and returns if IOC/LST bit is > set. This logic doesn't work if multiple TRBs are queued per > request and the IOC/LST bit is set on the last TRB of that request. > Consider an example where a queued request has multiple queued TRBs > and IOC/LST bit is set only for the last TRB. In this case, the Core > generates XferComplete/XferInProgress events only for the last TRB > (since IOC/LST are set only for the last TRB). As per the logic in > dwc3_gadget_ep_reclaim_completed_trb() event->status is checked for > IOC/LST bit and returns on the first TRB. This makes the remaining > TRBs left unhandled. > To aviod this, changed the code to check for IOC/LST bits in both > event->status & TRB->ctrl. This patch does the same. > > At a practical level, this patch resolves USB transfer stalls seen > with adb on dwc3 based Android devices after functionfs gadget > added scatter-gather support around v4.20. > > Cc: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> > Cc: Fei Yang <fei.yang@xxxxxxxxx> > Cc: Thinh Nguyen <thinhn@xxxxxxxxxxxx> > Cc: Tejas Joglekar <tejas.joglekar@xxxxxxxxxxxx> > Cc: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx> > Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> > Cc: Linux USB List <linux-usb@xxxxxxxxxxxxxxx> > Cc: stable <stable@xxxxxxxxxxxxxxx> > Tested-By: Tejas Joglekar <tejas.joglekar@xxxxxxxxxxxx> > Reviewed-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx> > Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xxxxxxxxxx> > [jstultz: forward ported to mainline, added note to commit log] > Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> > --- > Just wanted to send this out so we're all looking at the same thing. > Not sure if its correct, but it seems to solve the adb stalls I've > been seeing for awhile. Felipe: Any thoughts on this patch? thanks -john
