[PATCH 3/8] usb: xhci: Allow context state errors when halting an endpoint

[Hector Martin]

There is a race where an endpoint may halt by itself while we are trying
to halt it, which results in a context state error. See xHCI 4.6.9 which
mentions this case.

This also avoids BUGging when we attempt to stop an endpoint which was
already stopped to begin with, which is probably a bug elsewhere but
not a good reason to crash.

Signed-off-by: Hector Martin <marcan at marcan.st>
---
 drivers/usb/host/xhci-ring.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d08bb8e2bfba..5c2d16b58589 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -543,6 +543,7 @@ static void abort_td(struct usb_device *udev, int ep_index)
 	struct xhci_ctrl *ctrl = xhci_get_ctrl(udev);
 	struct xhci_ring *ring =  ctrl->devs[udev->slot_id]->eps[ep_index].ring;
 	union xhci_trb *event;
+	xhci_comp_code comp;
 	trb_type type;
 	u64 addr;
 	u32 field;
@@ -571,10 +572,11 @@ static void abort_td(struct usb_device *udev, int ep_index)
 		printf("abort_td: Expected a TRB_TRANSFER TRB first\n");
 	}
 
+	comp = GET_COMP_CODE(le32_to_cpu(event->event_cmd.status));
 	BUG_ON(type != TRB_COMPLETION ||
 		TRB_TO_SLOT_ID(le32_to_cpu(event->event_cmd.flags))
-		!= udev->slot_id || GET_COMP_CODE(le32_to_cpu(
-		event->event_cmd.status)) != COMP_SUCCESS);
+		!= udev->slot_id || (comp != COMP_SUCCESS && comp
+		!= COMP_CTX_STATE));
 	xhci_acknowledge_event(ctrl);
 
 	addr = xhci_trb_virt_to_dma(ring->enq_seg,

-- 
2.41.0