When a URB is cancled, xhci driver turns the untransferred trbs into no-ops. If an endpoint stalls on a no-op trb that belongs to the cancelled URB, the event handler won't reset the endpoint. Hence, it will stay halted.
Link: http://marc.info/?l=linux-usb&m=149582598330127&w=2 Signed-off-by: Lu Baolu <baolu...@linux.intel.com> --- drivers/usb/host/xhci-ring.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index c75cfe7..b1de9f2 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -2577,15 +2577,20 @@ static int handle_tx_event(struct xhci_hcd *xhci, (struct xhci_generic_trb *) ep_trb); /* - * No-op TRB should not trigger interrupts. - * If ep_trb is a no-op TRB, it means the - * corresponding TD has been cancelled. Just ignore - * the TD. + * No-op TRB could trigger interrupts in a case where + * a URB was killed and a STALL_ERROR happens right + * after the endpoint ring stopped. Reset the halted + * endpoint. Otherwise, the endpoint remains stalled + * indefinitely. */ if (trb_is_noop(ep_trb)) { - xhci_dbg(xhci, - "ep_trb is a no-op TRB. Skip it for slot %u ep %u\n", - slot_id, ep_index); + if (trb_comp_code == COMP_STALL_ERROR || + xhci_requires_manual_halt_cleanup(xhci, ep_ctx, + trb_comp_code)) + xhci_cleanup_halted_endpoint(xhci, slot_id, + ep_index, + ep_ring->stream_id, + td, EP_HARD_RESET); goto cleanup; } -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
