[3.19.y-ckt stable] Patch "xhci: Calculate old endpoints correctly on device reset" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    xhci: Calculate old endpoints correctly on device reset

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt6.

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

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From f7ecac0ada3ee28a11df6c89c14cfdd4e169c94a Mon Sep 17 00:00:00 2001
From: Brian Campbell <bacam at z273.org.uk>
Date: Tue, 21 Jul 2015 17:20:28 +0300
Subject: xhci: Calculate old endpoints correctly on device reset

commit 326124a027abc9a7f43f72dc94f6f0f7a55b02b3 upstream.

When resetting a device the number of active TTs may need to be
corrected by xhci_update_tt_active_eps, but the number of old active
endpoints supplied to it was always zero, so the number of TTs and the
bandwidth reserved for them was not updated, and could rise
unnecessarily.

This affected systems using Intel's Patherpoint chipset, which rely on
software bandwidth checking.  For example, a Lenovo X230 would lose the
ability to use ports on the docking station after enough suspend/resume
cycles because the bandwidth calculated would rise with every cycle when
a suitable device is attached.

The correct number of active endpoints is calculated in the same way as
in xhci_reserve_bandwidth.

Signed-off-by: Brian Campbell <bacam at z273.org.uk>
Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/host/xhci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index ee1cc0f..f2194a0 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3457,6 +3457,9 @@ int xhci_discover_or_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
 			return -EINVAL;
 	}

+	if (virt_dev->tt_info)
+		old_active_eps = virt_dev->tt_info->active_eps;
+
 	if (virt_dev->udev != udev) {
 		/* If the virt_dev and the udev does not match, this virt_dev
 		 * may belong to another udev.
--
1.9.1