1 files changed, 48 insertions, 8 deletions

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index a081ee65bde..07bcb931021 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -1004,7 +1004,8 @@ iso_stream_put(struct ehci_hcd *ehci, struct ehci_iso_stream *stream)
 
 		is_in = (stream->bEndpointAddress & USB_DIR_IN) ? 0x10 : 0;
 		stream->bEndpointAddress &= 0x0f;
-		stream->ep->hcpriv = NULL;
+		if (stream->ep)
+			stream->ep->hcpriv = NULL;
 
 		if (stream->rescheduled) {
 			ehci_info (ehci, "ep%d%s-iso rescheduled "
@@ -1653,14 +1654,28 @@ itd_complete (
 			(stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
 	}
 	iso_stream_put (ehci, stream);
-	/* OK to recycle this ITD now that its completion callback ran. */
+
 done:
 	usb_put_urb(urb);
 	itd->urb = NULL;
-	itd->stream = NULL;
-	list_move(&itd->itd_list, &stream->free_list);
-	iso_stream_put(ehci, stream);
-
+	if (ehci->clock_frame != itd->frame || itd->index[7] != -1) {
+		/* OK to recycle this ITD now. */
+		itd->stream = NULL;
+		list_move(&itd->itd_list, &stream->free_list);
+		iso_stream_put(ehci, stream);
+	} else {
+		/* HW might remember this ITD, so we can't recycle it yet.
+		 * Move it to a safe place until a new frame starts.
+		 */
+		list_move(&itd->itd_list, &ehci->cached_itd_list);
+		if (stream->refcount == 2) {
+			/* If iso_stream_put() were called here, stream
+			 * would be freed.  Instead, just prevent reuse.
+			 */
+			stream->ep->hcpriv = NULL;
+			stream->ep = NULL;
+		}
+	}
 	return retval;
 }
 
@@ -2101,6 +2116,20 @@ done:
 
 /*-------------------------------------------------------------------------*/
 
+static void free_cached_itd_list(struct ehci_hcd *ehci)
+{
+	struct ehci_itd *itd, *n;
+
+	list_for_each_entry_safe(itd, n, &ehci->cached_itd_list, itd_list) {
+		struct ehci_iso_stream	*stream = itd->stream;
+		itd->stream = NULL;
+		list_move(&itd->itd_list, &stream->free_list);
+		iso_stream_put(ehci, stream);
+	}
+}
+
+/*-------------------------------------------------------------------------*/
+
 static void
 scan_periodic (struct ehci_hcd *ehci)
 {
@@ -2115,10 +2144,17 @@ scan_periodic (struct ehci_hcd *ehci)
 	 * Touches as few pages as possible:  cache-friendly.
 	 */
 	now_uframe = ehci->next_uframe;
-	if (HC_IS_RUNNING (ehci_to_hcd(ehci)->state))
+	if (HC_IS_RUNNING(ehci_to_hcd(ehci)->state)) {
 		clock = ehci_readl(ehci, &ehci->regs->frame_index);
-	else
+		clock_frame = (clock >> 3) % ehci->periodic_size;
+	} else  {
 		clock = now_uframe + mod - 1;
+		clock_frame = -1;
+	}
+	if (ehci->clock_frame != clock_frame) {
+		free_cached_itd_list(ehci);
+		ehci->clock_frame = clock_frame;
+	}
 	clock %= mod;
 	clock_frame = clock >> 3;
 
@@ -2277,6 +2313,10 @@ restart:
 			/* rescan the rest of this frame, then ... */
 			clock = now;
 			clock_frame = clock >> 3;
+			if (ehci->clock_frame != clock_frame) {
+				free_cached_itd_list(ehci);
+				ehci->clock_frame = clock_frame;
+			}
 		} else {
 			now_uframe++;
 			now_uframe %= mod;