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;