--- drivers/usb/host/xhci-ring.c

+++ drivers/usb/host/xhci-ring.c

@@ -417,6 +417,20 @@ void xhci_find_new_dequeue_state(struct

state->new_cycle_state = ~(state->new_cycle_state) & 0x1;

next_trb(xhci, ep_ring, &state->new_deq_seg, &state->new_deq_ptr);

+ /*

+ * If there is only one segment in a ring, find_trb_seg()'s while loop

+ * will not run, and it will return before it has a chance to see if it

+ * needs to toggle the cycle bit. It can't tell if the stalled transfer

+ * ended just before the link TRB on a one-segment ring, or if the TD

+ * wrapped around the top of the ring, because it doesn't have the TD in

+ * question. Look for the one-segment case where stalled TRB's address

+ * is greater than the new dequeue pointer address.

+ */

+ if (ep_ring->first_seg == ep_ring->first_seg->next &&

+ state->new_deq_ptr < dev->eps[ep_index].stopped_trb)

+ state->new_cycle_state ^= 0x1;

+ xhci_dbg(xhci, "Cycle state = 0x%x\n", state->new_cycle_state);

+

/* Don't update the ring cycle state for the producer (us). */

xhci_dbg(xhci, "New dequeue segment = %p (virtual)\n",

state->new_deq_seg);