This is a note to let you know that I've just added the patch titled
USB: EHCI: fix bug in scheduling periodic split transfers
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-ehci-fix-bug-in-scheduling-periodic-split-transfers.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 3e619d04159be54b3daa0b7036b0ce9e067f4b5d Mon Sep 17 00:00:00 2001
From: Alan Stern <[email protected]>
Date: Wed, 30 Jan 2013 16:36:40 -0500
Subject: USB: EHCI: fix bug in scheduling periodic split transfers
From: Alan Stern <[email protected]>
commit 3e619d04159be54b3daa0b7036b0ce9e067f4b5d upstream.
This patch (as1654) fixes a very old bug in ehci-hcd, connected with
scheduling of periodic split transfers. The calculations for
full/low-speed bus usage are all carried out after the correction for
bit-stuffing has been applied, but the values in the max_tt_usecs
array assume it hasn't been. The array should allow for allocation of
up to 90% of the bus capacity, which is 900 us, not 780 us.
The symptom caused by this bug is that any isochronous transfer to a
full-speed device with a maxpacket size larger than about 980 bytes is
always rejected with a -ENOSPC error.
Signed-off-by: Alan Stern <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/host/ehci-sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -236,7 +236,7 @@ static inline unsigned char tt_start_ufr
}
static const unsigned char
-max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 };
+max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 125, 25 };
/* carryover low/fullspeed bandwidth that crosses uframe boundries */
static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8])
Patches currently in stable-queue which might be from [email protected]
are
queue-3.4/usb-ehci-fix-timer-bug-affecting-port-resume.patch
queue-3.4/usb-ehci-fix-bug-in-scheduling-periodic-split-transfers.patch
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