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-rw-r--r--drivers/usb/host/xhci-ring.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 974d49205569..38fb6820489d 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -417,6 +417,20 @@ void xhci_find_new_dequeue_state(struct xhci_hcd *xhci,
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);