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 HiKey960 after functionfs gadget added scatter-gather support around v4.20. Cc: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> Cc: Yang Fei <fei.yang@xxxxxxxxx> Cc: Thinh Nguyen <thinhn@xxxxxxxxxxxx> Cc: Tejas Joglekar <tejas.joglekar@xxxxxxxxxxxx> Cc: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx> Cc: Jack Pham <jackp@xxxxxxxxxxxxxx> Cc: Todd Kjos <tkjos@xxxxxxxxxx> 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> --- drivers/usb/dwc3/gadget.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 154f3f3e8cff..1edce3bbb55c 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2420,7 +2420,12 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep, if (event->status & DEPEVT_STATUS_SHORT && !chain) return 1; - if (event->status & DEPEVT_STATUS_IOC) + if ((event->status & DEPEVT_STATUS_IOC) && + (trb->ctrl & DWC3_TRB_CTRL_IOC)) + return 1; + + if ((event->status & DEPEVT_STATUS_LST) && + (trb->ctrl & DWC3_TRB_CTRL_LST)) return 1; return 0; -- 2.17.1
