[3.16.y-ckt stable] Patch "xhci: give command abortion one more chance before killing xhci" has been added to staging queue

[Luis Henriques]

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

    xhci: give command abortion one more chance before killing xhci

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt19.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 7d31f0cc3c4a329f38a4354062f96eee23654363 Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman at linux.intel.com>
Date: Mon, 21 Sep 2015 17:46:10 +0300
Subject: xhci: give command abortion one more chance before killing xhci

commit a6809ffd1687b3a8c192960e69add559b9d32649 upstream.

We want to give the command abortion an additional try to stop
the command ring before we completely hose xhci.

Tested-by: Vincent Pelletier <plr.vincent at gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman at linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
[ luis: backported to 3.16:
  - xhci_handshake() has an extra 'xhci' parameter in 3.16 ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/host/xhci-ring.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 735659f69599..79143b8d1889 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -302,6 +302,15 @@ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci)
 	ret = xhci_handshake(xhci, &xhci->op_regs->cmd_ring,
 			CMD_RING_RUNNING, 0, 5 * 1000 * 1000);
 	if (ret < 0) {
+		/* we are about to kill xhci, give it one more chance */
+		xhci_write_64(xhci, temp_64 | CMD_RING_ABORT,
+			      &xhci->op_regs->cmd_ring);
+		udelay(1000);
+		ret = xhci_handshake(xhci, &xhci->op_regs->cmd_ring,
+				     CMD_RING_RUNNING, 0, 3 * 1000 * 1000);
+		if (ret == 0)
+			return 0;
+
 		xhci_err(xhci, "Stopped the command ring failed, "
 				"maybe the host is dead\n");
 		xhci->xhc_state |= XHCI_STATE_DYING;