USB: EHCI: fix bug in Iso scheduling

[linux-2.6-omap-h63xx.git] / drivers / usb / host / ehci-sched.c

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index be575e46eac3132a661479a9138fcf64ea3a73ae..b7853c8bac0fb58c3c7f74e18145362b6f2002cd 100644 (file)
--- 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;