1 files changed, 9 insertions, 10 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index b906bc2eea5f..423bf3649570 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -699,7 +699,7 @@ static int xhci_move_dequeue_past_td(struct xhci_hcd *xhci,
 	int new_cycle;
 	dma_addr_t addr;
 	u64 hw_dequeue;
-	bool cycle_found = false;
+	bool hw_dequeue_found = false;
 	bool td_last_trb_found = false;
 	u32 trb_sct = 0;
 	int ret;
@@ -715,25 +715,24 @@ static int xhci_move_dequeue_past_td(struct xhci_hcd *xhci,
 	hw_dequeue = xhci_get_hw_deq(xhci, dev, ep_index, stream_id);
 	new_seg = ep_ring->deq_seg;
 	new_deq = ep_ring->dequeue;
-	new_cycle = hw_dequeue & 0x1;
+	new_cycle = le32_to_cpu(td->end_trb->generic.field[3]) & TRB_CYCLE;
 
 	/*
-	 * We want to find the pointer, segment and cycle state of the new trb
-	 * (the one after current TD's end_trb). We know the cycle state at
-	 * hw_dequeue, so walk the ring until both hw_dequeue and end_trb are
-	 * found.
+	 * Walk the ring until both the next TRB and hw_dequeue are found (don't
+	 * move hw_dequeue back if it went forward due to a HW bug). Cycle state
+	 * is loaded from a known good TRB, track later toggles to maintain it.
 	 */
 	do {
-		if (!cycle_found && xhci_trb_virt_to_dma(new_seg, new_deq)
+		if (!hw_dequeue_found && xhci_trb_virt_to_dma(new_seg, new_deq)
 		    == (dma_addr_t)(hw_dequeue & ~0xf)) {
-			cycle_found = true;
+			hw_dequeue_found = true;
 			if (td_last_trb_found)
 				break;
 		}
 		if (new_deq == td->end_trb)
 			td_last_trb_found = true;
 
-		if (cycle_found && trb_is_link(new_deq) &&
+		if (td_last_trb_found && trb_is_link(new_deq) &&
 		    link_trb_toggles_cycle(new_deq))
 			new_cycle ^= 0x1;
 
@@ -745,7 +744,7 @@ static int xhci_move_dequeue_past_td(struct xhci_hcd *xhci,
 			return -EINVAL;
 		}
 
-	} while (!cycle_found || !td_last_trb_found);
+	} while (!hw_dequeue_found || !td_last_trb_found);
 
 	/* Don't update the ring cycle state for the producer (us). */
 	addr = xhci_trb_virt_to_dma(new_seg, new_deq);