1 files changed, 27 insertions, 14 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 001b2c389be2..8a8e08a51ba3 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -2123,17 +2123,9 @@ scan_periodic (struct ehci_hcd *ehci)
         for (;;) {
                 union ehci_shadow       q, *q_p;
                 __hc32                  type, *hw_p;
-                unsigned                uframes;
+                unsigned                incomplete = false;
 
-                /* don't scan past the live uframe */
                 frame = now_uframe >> 3;
-                if (frame == (clock >> 3))
-                        uframes = now_uframe & 0x07;
-                else {
-                        /* safe to scan the whole frame at once */
-                        now_uframe |= 0x07;
-                        uframes = 8;
-                }
 
 restart:
                 /* scan each element in frame's queue for completions */
@@ -2171,12 +2163,15 @@ restart:
                                 q = q.fstn->fstn_next;
                                 break;
                         case Q_TYPE_ITD:
-                                /* skip itds for later in the frame */
+                                /* If this ITD is still active, leave it for
+                                 * later processing ... check the next entry.
+                                 */
                                 rmb ();
-                                for (uf = live ? uframes : 8; uf < 8; uf++) {
+                                for (uf = 0; uf < 8 && live; uf++) {
                                         if (0 == (q.itd->hw_transaction [uf]
                                                         & ITD_ACTIVE(ehci)))
                                                 continue;
+                                        incomplete = true;
                                         q_p = &q.itd->itd_next;
                                         hw_p = &q.itd->hw_next;
                                         type = Q_NEXT_TYPE(ehci,
@@ -2184,10 +2179,12 @@ restart:
                                         q = *q_p;
                                         break;
                                 }
-                                if (uf != 8)
+                                if (uf < 8 && live)
                                         break;
 
-                                /* this one's ready ... HC won't cache the
+                                /* Take finished ITDs out of the schedule
+                                 * and process them:  recycle, maybe report
+                                 * URB completion.  HC won't cache the
                                  * pointer for much longer, if at all.
                                  */
                                 *q_p = q.itd->itd_next;
@@ -2198,8 +2195,12 @@ restart:
                                 q = *q_p;
                                 break;
                         case Q_TYPE_SITD:
+                                /* If this SITD is still active, leave it for
+                                 * later processing ... check the next entry.
+                                 */
                                 if ((q.sitd->hw_results & SITD_ACTIVE(ehci))
                                                 && live) {
+                                        incomplete = true;
                                         q_p = &q.sitd->sitd_next;
                                         hw_p = &q.sitd->hw_next;
                                         type = Q_NEXT_TYPE(ehci,
@@ -2207,6 +2208,11 @@ restart:
                                         q = *q_p;
                                         break;
                                 }
+
+                                /* Take finished SITDs out of the schedule
+                                 * and process them:  recycle, maybe report
+                                 * URB completion.
+                                 */
                                 *q_p = q.sitd->sitd_next;
                                 *hw_p = q.sitd->hw_next;
                                 type = Q_NEXT_TYPE(ehci, q.sitd->hw_next);
@@ -2232,7 +2238,14 @@ restart:
                         }
                 }
 
-                /* stop when we catch up to the HC */
+                /* If we can tell we caught up to the hardware, stop now.
+                 * We can't advance our scan without collecting the ISO
+                 * transfers that are still pending in this frame.
+                 */
+                if (incomplete && HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
+                        ehci->next_uframe = now_uframe;
+                        break;
+                }
 
                 // FIXME:  this assumes we won't get lapped when
                 // latencies climb; that should be rare, but...