1 files changed, 44 insertions, 23 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index be575e46eac3..b7853c8bac0f 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -1349,18 +1349,27 @@ iso_stream_schedule (
 	/* when's the last uframe this urb could start? */
 	max = now + mod;
 
-	/* typical case: reuse current schedule. stream is still active,
-	 * and no gaps from host falling behind (irq delays etc)
+	/* Typical case: reuse current schedule, stream is still active.
+	 * Hopefully there are no gaps from the host falling behind
+	 * (irq delays etc), but if there are we'll take the next
+	 * slot in the schedule, implicitly assuming URB_ISO_ASAP.
 	 */
 	if (likely (!list_empty (&stream->td_list))) {
 		start = stream->next_uframe;
 		if (start < now)
 			start += mod;
-		if (likely ((start + sched->span) < max))
-			goto ready;
-		/* else fell behind; someday, try to reschedule */
-		status = -EL2NSYNC;
-		goto fail;
+
+		/* Fell behind (by up to twice the slop amount)? */
+		if (start >= max - 2 * 8 * SCHEDULE_SLOP)
+			start += stream->interval * DIV_ROUND_UP(
+					max - start, stream->interval) - mod;
+
+		/* Tried to schedule too far into the future? */
+		if (unlikely((start + sched->span) >= max)) {
+			status = -EFBIG;
+			goto fail;
+		}
+		goto ready;
 	}
 
 	/* need to schedule; when's the next (u)frame we could start?
@@ -1613,6 +1622,9 @@ itd_complete (
 		} else if (likely ((t & EHCI_ISOC_ACTIVE) == 0)) {
 			desc->status = 0;
 			desc->actual_length = EHCI_ITD_LENGTH (t);
+		} else {
+			/* URB was too late */
+			desc->status = -EXDEV;
 		}
 	}
 
@@ -2095,7 +2107,7 @@ done:
 static void
 scan_periodic (struct ehci_hcd *ehci)
 {
-	unsigned	frame, clock, now_uframe, mod;
+	unsigned	now_uframe, frame, clock, clock_frame, mod;
 	unsigned	modified;
 
 	mod = ehci->periodic_size << 3;
@@ -2111,6 +2123,7 @@ scan_periodic (struct ehci_hcd *ehci)
 	else
 		clock = now_uframe + mod - 1;
 	clock %= mod;
+	clock_frame = clock >> 3;
 
 	for (;;) {
 		union ehci_shadow	q, *q_p;
@@ -2157,22 +2170,26 @@ restart:
 			case Q_TYPE_ITD:
 				/* If this ITD is still active, leave it for
 				 * later processing ... check the next entry.
+				 * No need to check for activity unless the
+				 * frame is current.
 				 */
-				rmb ();
-				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,
+				if (frame == clock_frame && live) {
+					rmb();
+					for (uf = 0; uf < 8; uf++) {
+						if (q.itd->hw_transaction[uf] &
+							    ITD_ACTIVE(ehci))
+							break;
+					}
+					if (uf < 8) {
+						incomplete = true;
+						q_p = &q.itd->itd_next;
+						hw_p = &q.itd->hw_next;
+						type = Q_NEXT_TYPE(ehci,
 							q.itd->hw_next);
-					q = *q_p;
-					break;
+						q = *q_p;
+						break;
+					}
 				}
-				if (uf < 8 && live)
-					break;
 
 				/* Take finished ITDs out of the schedule
 				 * and process them:  recycle, maybe report
@@ -2189,9 +2206,12 @@ restart:
 			case Q_TYPE_SITD:
 				/* If this SITD is still active, leave it for
 				 * later processing ... check the next entry.
+				 * No need to check for activity unless the
+				 * frame is current.
 				 */
-				if ((q.sitd->hw_results & SITD_ACTIVE(ehci))
-						&& live) {
+				if (frame == clock_frame && live &&
+						(q.sitd->hw_results &
+							SITD_ACTIVE(ehci))) {
 					incomplete = true;
 					q_p = &q.sitd->sitd_next;
 					hw_p = &q.sitd->hw_next;
@@ -2260,6 +2280,7 @@ restart:
 
 			/* rescan the rest of this frame, then ... */
 			clock = now;
+			clock_frame = clock >> 3;
 		} else {
 			now_uframe++;
 			now_uframe %= mod;