EHCI: implement new semantics for URB_ISO_ASAP

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 <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index e08e65d8e0047a407136f35c4f281fd075af0a28..b538a4d62d5ee89ff83f2f3554d86461652d5fb6 100644 (file)
--- a/drivers/usb/host/ehci-sched.c
+++ b/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 *ehci, struct ehci_itd *itd)
                        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_hcd *ehci, struct ehci_sitd *sitd)
        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_hcd *ehci, struct ehci_sitd *sitd)
                        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);