Patchwork [3.5.y.z,extended,stable] Patch "xhci: Handle HS bulk/ctrl endpoints that don't NAK." has been added to staging queue

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Submitter Herton Ronaldo Krzesinski
Date Jan. 23, 2013, 4:41 a.m.
Message ID <1358916063-21484-1-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/214729/
State New
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Comments

Herton Ronaldo Krzesinski - Jan. 23, 2013, 4:41 a.m.
This is a note to let you know that I have just added a patch titled

    xhci: Handle HS bulk/ctrl endpoints that don't NAK.

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

From 99f9541901477ae965e04848f2c0da84f839fc01 Mon Sep 17 00:00:00 2001
From: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Date: Mon, 17 Dec 2012 14:12:35 -0800
Subject: [PATCH] xhci: Handle HS bulk/ctrl endpoints that don't NAK.

commit 55c1945edaac94c5338a3647bc2e85ff75d9cf36 upstream.

A high speed control or bulk endpoint may have bInterval set to zero,
which means it does not NAK.  If bInterval is non-zero, it means the
endpoint NAKs at a rate of 2^(bInterval - 1).

The xHCI code to compute the NAK interval does not handle the special
case of zero properly.  The current code unconditionally subtracts one
from bInterval and uses it as an exponent.  This causes a very large
bInterval to be used, and warning messages like these will be printed:

usb 1-1: ep 0x1 - rounding interval to 32768 microframes, ep desc says 0 microframes

This may cause the xHCI host hardware to reject the Configure Endpoint
command, which means the HS device will be unusable under xHCI ports.

This patch should be backported to kernels as old as 2.6.31, that contain
commit dfa49c4ad120a784ef1ff0717168aa79f55a483a "USB: xhci - fix math in
xhci_get_endpoint_interval()".

Reported-by: Vincent Pelletier <plr.vincent@gmail.com>
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 drivers/usb/host/xhci-mem.c |    2 ++
 1 file changed, 2 insertions(+)

--
1.7.9.5

Patch

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index fb51c70..35616ff 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1250,6 +1250,8 @@  static unsigned int xhci_microframes_to_exponent(struct usb_device *udev,
 static unsigned int xhci_parse_microframe_interval(struct usb_device *udev,
 		struct usb_host_endpoint *ep)
 {
+	if (ep->desc.bInterval == 0)
+		return 0;
 	return xhci_microframes_to_exponent(udev, ep,
 			ep->desc.bInterval, 0, 15);
 }