This patch (as1612) updates the isochronous scheduling and processing
in ehci-hcd to match the new semantics for URB_ISO_ASAP. It also adds
a missing "unlikely" in sitd_complete() to match the corresponding
statement in itd_complete(), and it increments urb->error_count in a
couple of places that had been overlooked.
Signed-off-by: Alan Stern <st...@rowland.harvard.edu>
---
drivers/usb/host/ehci-sched.c | 33 ++++++++++++++++++++++++++-------
1 file changed, 26 insertions(+), 7 deletions(-)
Index: usb-3.6/drivers/usb/host/ehci-sched.c
===================================================================
--- usb-3.6.orig/drivers/usb/host/ehci-sched.c
+++ usb-3.6/drivers/usb/host/ehci-sched.c
@@ -1386,8 +1386,8 @@ iso_stream_schedule (
/* 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.
+ * (irq delays etc). If there are, the behavior depends on
+ * whether URB_ISO_ASAP is set.
*/
if (likely (!list_empty (&stream->td_list))) {
@@ -1414,9 +1414,25 @@ iso_stream_schedule (
goto fail;
}
- /* Behind the scheduling threshold? Assume URB_ISO_ASAP. */
- if (unlikely(start < next))
- start += (next - start + period - 1) & (- period);
+ /* Behind the scheduling threshold? */
+ if (unlikely(start < next)) {
+
+ /* USB_ISO_ASAP: Round up to the first available slot */
+ if (urb->transfer_flags & URB_ISO_ASAP)
+ start += (next - start + period - 1) & -period;
+
+ /*
+ * Not ASAP: Use the next slot in the stream. If
+ * the entire URB falls before the threshold, fail.
+ */
+ else if (start + span - period < next) {
+ ehci_dbg(ehci, "iso urb late %p (%u+%u < %u)\n",
+ urb, start + base,
+ span - period, next + base);
+ status = -EXDEV;
+ goto fail;
+ }
+ }
start += base;
}
@@ -1699,7 +1715,7 @@ static bool itd_complete(struct ehci_hcd
urb->actual_length += desc->actual_length;
} else {
/* URB was too late */
- desc->status = -EXDEV;
+ urb->error_count++;
}
}
@@ -2072,7 +2088,7 @@ static bool sitd_complete(struct ehci_hc
t = hc32_to_cpup(ehci, &sitd->hw_results);
/* report transfer status */
- if (t & SITD_ERRS) {
+ if (unlikely(t & SITD_ERRS)) {
urb->error_count++;
if (t & SITD_STS_DBE)
desc->status = usb_pipein (urb->pipe)
@@ -2082,6 +2098,9 @@ static bool sitd_complete(struct ehci_hc
desc->status = -EOVERFLOW;
else /* XACT, MMF, etc */
desc->status = -EPROTO;
+ } else if (unlikely(t & SITD_STS_ACTIVE)) {
+ /* URB was too late */
+ urb->error_count++;
} else {
desc->status = 0;
desc->actual_length = desc->length - SITD_LENGTH(t);
--
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