1 files changed, 11 insertions, 4 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index aa88a067148b..011458f4d9ce 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -172,8 +172,9 @@ static void inc_deq(struct xhci_hcd *xhci, struct xhci_ring *ring, bool consumer
  * have their chain bit cleared (so that each Link TRB is a separate TD).
  *
  * Section 6.4.4.1 of the 0.95 spec says link TRBs cannot have the chain bit
- * set, but other sections talk about dealing with the chain bit set.
- * Assume section 6.4.4.1 is wrong, and the chain bit can be set in a Link TRB.
+ * set, but other sections talk about dealing with the chain bit set.  This was
+ * fixed in the 0.96 specification errata, but we have to assume that all 0.95
+ * xHCI hardware can't handle the chain bit being cleared on a link TRB.
  */
 static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring, bool consumer)
 {
@@ -191,8 +192,14 @@ static void inc_enq(struct xhci_hcd *xhci, struct xhci_ring *ring, bool consumer
         while (last_trb(xhci, ring, ring->enq_seg, next)) {
                 if (!consumer) {
                         if (ring != xhci->event_ring) {
-                                next->link.control &= ~TRB_CHAIN;
-                                next->link.control |= chain;
+                                /* If we're not dealing with 0.95 hardware,
+                                 * carry over the chain bit of the previous TRB
+                                 * (which may mean the chain bit is cleared).
+                                 */
+                                if (!xhci_link_trb_quirk(xhci)) {
+                                        next->link.control &= ~TRB_CHAIN;
+                                        next->link.control |= chain;
+                                }
                                 /* Give this link TRB to the hardware */
                                 wmb();
                                 if (next->link.control & TRB_CYCLE)