This is a note to let you know that I've just added the patch titled
USB: OHCI: fix logic for scheduling isochronous URBs
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 815fa7b917614261748d1ecd9600ff27f99508e5 Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Date: Tue, 14 May 2013 13:57:51 -0400
Subject: USB: OHCI: fix logic for scheduling isochronous URBs
The isochronous scheduling logic in ohci-hcd has a bug. The
calculation for skipping TDs that are too late should be carried out
only in the !URB_ISO_ASAP case. When URB_ISO_ASAP is set, the URB is
pushed back so that none of the TDs are too late, which would cause
the calculation to overflow.
The patch also fixes the calculation to avoid overflow in the case
where the frame value wraps around.
This should be applied to -stable kernels going back to 3.8.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
CC: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/ohci-hcd.c | 32 ++++++++++++++++++--------------
1 file changed, 18 insertions(+), 14 deletions(-)
diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index df1af0b..fc627fd 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -240,7 +240,7 @@ static int ohci_urb_enqueue (
if (unlikely(tick_before(frame, next))) {
/* USB_ISO_ASAP: Round up to the first available slot */
- if (urb->transfer_flags & URB_ISO_ASAP)
+ if (urb->transfer_flags & URB_ISO_ASAP) {
frame += (next - frame + ed->interval - 1) &
-ed->interval;
@@ -248,21 +248,25 @@ static int ohci_urb_enqueue (
* Not ASAP: Use the next slot in the stream. If
* the entire URB falls before the threshold, fail.
*/
- else if (tick_before(frame + ed->interval *
+ } else {
+ if (tick_before(frame + ed->interval *
(urb->number_of_packets - 1), next)) {
- retval = -EXDEV;
- usb_hcd_unlink_urb_from_ep(hcd, urb);
- goto fail;
- }
+ retval = -EXDEV;
+ usb_hcd_unlink_urb_from_ep(hcd, urb);
+ goto fail;
+ }
- /*
- * Some OHCI hardware doesn't handle late TDs
- * correctly. After retiring them it proceeds to
- * the next ED instead of the next TD. Therefore
- * we have to omit the late TDs entirely.
- */
- urb_priv->td_cnt = DIV_ROUND_UP(next - frame,
- ed->interval);
+ /*
+ * Some OHCI hardware doesn't handle late TDs
+ * correctly. After retiring them it proceeds
+ * to the next ED instead of the next TD.
+ * Therefore we have to omit the late TDs
+ * entirely.
+ */
+ urb_priv->td_cnt = DIV_ROUND_UP(
+ (u16) (next - frame),
+ ed->interval);
+ }
}
urb->start_frame = frame;
}
--
1.8.3.rc1.46.g4a27aed
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