1 files changed, 35 insertions, 16 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 23b4aefd1036..643c2f3f3e73 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -145,29 +145,37 @@ static void next_trb(struct xhci_hcd *xhci,
  */
 static void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring)
 {
-	union xhci_trb *next;
 	unsigned long long addr;
 
 	ring->deq_updates++;
 
-	/* If this is not event ring, there is one more usable TRB */
+	/*
+	 * If this is not event ring, and the dequeue pointer
+	 * is not on a link TRB, there is one more usable TRB
+	 */
 	if (ring->type != TYPE_EVENT &&
 			!last_trb(xhci, ring, ring->deq_seg, ring->dequeue))
 		ring->num_trbs_free++;
-	next = ++(ring->dequeue);
 
-	/* Update the dequeue pointer further if that was a link TRB or we're at
-	 * the end of an event ring segment (which doesn't have link TRBS)
-	 */
-	while (last_trb(xhci, ring, ring->deq_seg, next)) {
-		if (ring->type == TYPE_EVENT &&	last_trb_on_last_seg(xhci,
-				ring, ring->deq_seg, next)) {
-			ring->cycle_state = (ring->cycle_state ? 0 : 1);
+	do {
+		/*
+		 * Update the dequeue pointer further if that was a link TRB or
+		 * we're at the end of an event ring segment (which doesn't have
+		 * link TRBS)
+		 */
+		if (last_trb(xhci, ring, ring->deq_seg, ring->dequeue)) {
+			if (ring->type == TYPE_EVENT &&
+					last_trb_on_last_seg(xhci, ring,
+						ring->deq_seg, ring->dequeue)) {
+				ring->cycle_state = (ring->cycle_state ? 0 : 1);
+			}
+			ring->deq_seg = ring->deq_seg->next;
+			ring->dequeue = ring->deq_seg->trbs;
+		} else {
+			ring->dequeue++;
 		}
-		ring->deq_seg = ring->deq_seg->next;
-		ring->dequeue = ring->deq_seg->trbs;
-		next = ring->dequeue;
-	}
+	} while (last_trb(xhci, ring, ring->deq_seg, ring->dequeue));
+
 	addr = (unsigned long long) xhci_trb_virt_to_dma(ring->deq_seg, ring->dequeue);
 }
 
@@ -885,6 +893,17 @@ static void update_ring_for_set_deq_completion(struct xhci_hcd *xhci,
 	num_trbs_free_temp = ep_ring->num_trbs_free;
 	dequeue_temp = ep_ring->dequeue;
 
+	/* If we get two back-to-back stalls, and the first stalled transfer
+	 * ends just before a link TRB, the dequeue pointer will be left on
+	 * the link TRB by the code in the while loop.  So we have to update
+	 * the dequeue pointer one segment further, or we'll jump off
+	 * the segment into la-la-land.
+	 */
+	if (last_trb(xhci, ep_ring, ep_ring->deq_seg, ep_ring->dequeue)) {
+		ep_ring->deq_seg = ep_ring->deq_seg->next;
+		ep_ring->dequeue = ep_ring->deq_seg->trbs;
+	}
+
 	while (ep_ring->dequeue != dev->eps[ep_index].queued_deq_ptr) {
 		/* We have more usable TRBs */
 		ep_ring->num_trbs_free++;
@@ -2062,8 +2081,8 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 		if (xhci->quirks & XHCI_TRUST_TX_LENGTH)
 			trb_comp_code = COMP_SHORT_TX;
 		else
-			xhci_warn(xhci, "WARN Successful completion on short TX: "
-					"needs XHCI_TRUST_TX_LENGTH quirk?\n");
+			xhci_warn_ratelimited(xhci,
+					"WARN Successful completion on short TX: needs XHCI_TRUST_TX_LENGTH quirk?\n");
 	case COMP_SHORT_TX:
 		break;
 	case COMP_STOP: