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-rw-r--r--drivers/usb/host/ehci-sched.c110
1 files changed, 57 insertions, 53 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index dd37350170b..3381319a2b3 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -1413,13 +1413,6 @@ iso_stream_schedule (
goto fail;
}
- if (stream->depth + span > mod) {
- ehci_dbg (ehci, "request %p would overflow (%d+%d>%d)\n",
- urb, stream->depth, span, mod);
- status = -EFBIG;
- goto fail;
- }
-
now = ehci_readl(ehci, &ehci->regs->frame_index) & (mod - 1);
/* Typical case: reuse current schedule, stream is still active.
@@ -1428,7 +1421,7 @@ iso_stream_schedule (
* slot in the schedule, implicitly assuming URB_ISO_ASAP.
*/
if (likely (!list_empty (&stream->td_list))) {
- start = stream->next_uframe;
+ u32 excess;
/* For high speed devices, allow scheduling within the
* isochronous scheduling threshold. For full speed devices
@@ -1440,21 +1433,23 @@ iso_stream_schedule (
else
next = now;
- /* Fell behind (by up to twice the slop amount)? */
- if (((start - next) & (mod - 1)) >=
- mod - 2 * SCHEDULE_SLOP)
- start += period * DIV_ROUND_UP(
- (next - start) & (mod - 1),
- period);
-
- /* Tried to schedule too far into the future? */
- if (unlikely(((start - now) & (mod - 1)) + span
- >= mod - 2 * SCHEDULE_SLOP)) {
+ /* Fell behind (by up to twice the slop amount)?
+ * We decide based on the time of the last currently-scheduled
+ * slot, not the time of the next available slot.
+ */
+ excess = (stream->next_uframe - period - next) & (mod - 1);
+ if (excess >= mod - 2 * SCHEDULE_SLOP)
+ start = next + excess - mod + period *
+ DIV_ROUND_UP(mod - excess, period);
+ else
+ start = next + excess + period;
+ if (start - now >= mod) {
+ ehci_dbg(ehci, "request %p would overflow (%d+%d >= %d)\n",
+ urb, start - now - period, period,
+ mod);
status = -EFBIG;
goto fail;
}
- stream->next_uframe = start;
- goto ready;
}
/* need to schedule; when's the next (u)frame we could start?
@@ -1463,51 +1458,60 @@ iso_stream_schedule (
* can also help high bandwidth if the dma and irq loads don't
* jump until after the queue is primed.
*/
- start = SCHEDULE_SLOP + (now & ~0x07);
- start &= mod - 1;
- stream->next_uframe = start;
-
- /* NOTE: assumes URB_ISO_ASAP, to limit complexity/bugs */
-
- /* find a uframe slot with enough bandwidth */
- for (; start < (stream->next_uframe + period); start++) {
- int enough_space;
-
- /* check schedule: enough space? */
- if (stream->highspeed)
- enough_space = itd_slot_ok (ehci, mod, start,
- stream->usecs, period);
- else {
- if ((start % 8) >= 6)
- continue;
- enough_space = sitd_slot_ok (ehci, mod, stream,
- start, sched, period);
+ else {
+ start = SCHEDULE_SLOP + (now & ~0x07);
+
+ /* NOTE: assumes URB_ISO_ASAP, to limit complexity/bugs */
+
+ /* find a uframe slot with enough bandwidth */
+ next = start + period;
+ for (; start < next; start++) {
+
+ /* check schedule: enough space? */
+ if (stream->highspeed) {
+ if (itd_slot_ok(ehci, mod, start,
+ stream->usecs, period))
+ break;
+ } else {
+ if ((start % 8) >= 6)
+ continue;
+ if (sitd_slot_ok(ehci, mod, stream,
+ start, sched, period))
+ break;
+ }
}
- /* schedule it here if there's enough bandwidth */
- if (enough_space) {
- stream->next_uframe = start & (mod - 1);
- goto ready;
+ /* no room in the schedule */
+ if (start == next) {
+ ehci_dbg(ehci, "iso resched full %p (now %d max %d)\n",
+ urb, now, now + mod);
+ status = -ENOSPC;
+ goto fail;
}
}
- /* no room in the schedule */
- ehci_dbg (ehci, "iso %ssched full %p (now %d max %d)\n",
- list_empty (&stream->td_list) ? "" : "re",
- urb, now, now + mod);
- status = -ENOSPC;
+ /* Tried to schedule too far into the future? */
+ if (unlikely(start - now + span - period
+ >= mod - 2 * SCHEDULE_SLOP)) {
+ ehci_dbg(ehci, "request %p would overflow (%d+%d >= %d)\n",
+ urb, start - now, span - period,
+ mod - 2 * SCHEDULE_SLOP);
+ status = -EFBIG;
+ goto fail;
+ }
-fail:
- iso_sched_free (stream, sched);
- urb->hcpriv = NULL;
- return status;
+ stream->next_uframe = start & (mod - 1);
-ready:
/* report high speed start in uframes; full speed, in frames */
urb->start_frame = stream->next_uframe;
if (!stream->highspeed)
urb->start_frame >>= 3;
return 0;
+
+ fail:
+ iso_sched_free(stream, sched);
+ urb->hcpriv = NULL;
+ return status;
}
/*-------------------------------------------------------------------------*/