xhci: Properly handle COMP_2ND_BW_ERR
authorHans de Goede <hdegoede@redhat.com>
Wed, 4 Jan 2012 22:29:18 +0000 (23:29 +0100)
committerGreg Kroah-Hartman <gregkh@suse.de>
Thu, 12 Jan 2012 19:33:35 +0000 (11:33 -0800)
commit6840a1e10529e7142e22c7308d7db4b4fa9a6d8f
treefd9fbf357e97e8537282cee8451ecb9f1e8c6e79
parent699b357681825b82f9c7d4465d04a1ee714fed76
xhci: Properly handle COMP_2ND_BW_ERR

commit 71d85724bdd947a3b42a88d08af79f290a1a767b upstream.

I encountered a result of COMP_2ND_BW_ERR while improving how the pwc
webcam driver handles not having the full usb1 bandwidth available to
itself.

I created the following test setup, a NEC xhci controller with a
single TT USB 2 hub plugged into it, with a usb keyboard and a pwc webcam
plugged into the usb2 hub. This caused the following to show up in dmesg
when trying to stream from the pwc camera at its highest alt setting:

xhci_hcd 0000:01:00.0: ERROR: unexpected command completion code 0x23.
usb 6-2.1: Not enough bandwidth for altsetting 9

And usb_set_interface returned -EINVAL, which caused my pwc code to not
do the right thing as it expected -ENOSPC.

This patch makes the xhci driver properly handle COMP_2ND_BW_ERR and makes
usb_set_interface return -ENOSPC as expected.

This should be backported to stable kernels as old as 2.6.32.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/host/xhci.c
drivers/usb/host/xhci.h