This is a note to let you know that I've just added the patch titled
xhci: correct burst count field for isoc transfers on 1.0 xhci hosts
to the 3.15-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:
xhci-correct-burst-count-field-for-isoc-transfers-on-1.0-xhci-hosts.patch
and it can be found in the queue-3.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 3213b151387df0b95f4eada104f68eb1c1409cb3 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Date: Tue, 24 Jun 2014 17:14:41 +0300
Subject: xhci: correct burst count field for isoc transfers on 1.0 xhci hosts
From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
commit 3213b151387df0b95f4eada104f68eb1c1409cb3 upstream.
The transfer burst count (TBC) field in xhci 1.0 hosts should be set
to the number of bursts needed to transfer all packets in a isoc TD.
Supported values are 0-2 (1 to 3 bursts per service interval).
Formula for TBC calculation is given in xhci spec section 4.11.2.3:
TBC = roundup( Transfer Descriptor Packet Count / Max Burst Size +1 ) - 1
This patch should be applied to stable kernels since 3.0 that contain
the commit 5cd43e33b9519143f06f507dd7cbee6b7a621885
"xhci 1.0: Set transfer burst count field."
Suggested-by: ShiChun Ma <masc2008@xxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-ring.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3699,7 +3699,7 @@ static unsigned int xhci_get_burst_count
return 0;
max_burst = urb->ep->ss_ep_comp.bMaxBurst;
- return roundup(total_packet_count, max_burst + 1) - 1;
+ return DIV_ROUND_UP(total_packet_count, max_burst + 1) - 1;
}
/*
Patches currently in stable-queue which might be from mathias.nyman@xxxxxxxxxxxxxxx are
queue-3.15/xhci-use-correct-slot-id-when-handling-a-reset-device-command.patch
queue-3.15/xhci-fix-runtime-suspended-xhci-from-blocking-system-suspend.patch
queue-3.15/xhci-correct-burst-count-field-for-isoc-transfers-on-1.0-xhci-hosts.patch
--
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