[3.13.y-ckt stable] Patch "USB: xhci: don't start a halted endpoint before its new dequeue is set" has been added to staging queue

[Kamal Mostafa]

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

    USB: xhci: don't start a halted endpoint before its new dequeue is set

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt13.

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

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 3582fda87156fbdfff4ff73c53b609000e74d03a Mon Sep 17 00:00:00 2001
From: Mathias Nyman <mathias.nyman at linux.intel.com>
Date: Tue, 18 Nov 2014 11:27:11 +0200
Subject: USB: xhci: don't start a halted endpoint before its new dequeue is
 set

commit c3492dbfa1050debf23a5b5cd2bc7514c5b37896 upstream.

A halted endpoint ring must first be reset, then move the ring
dequeue pointer past the problematic TRB. If we start the ring too
early after reset, but before moving the dequeue pointer we
will end up executing the same problematic TRB again.

As we always issue a set transfer dequeue command after a reset
endpoint command we can skip starting endpoint rings at reset endpoint
command completion.

Without this fix we end up trying to handle the same faulty TD for
contol endpoints. causing timeout, and failing testusb ctrl_out write
tests.

Fixes: e9df17e (USB: xhci: Correct assumptions about number of rings per endpoint.)
Tested-by: Felipe Balbi <balbi at ti.com>
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-ring.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 58c2eac..1d84081 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1197,9 +1197,8 @@ static void xhci_handle_cmd_reset_ep(struct xhci_hcd *xhci, int slot_id,
 				false);
 		xhci_ring_cmd_db(xhci);
 	} else {
-		/* Clear our internal halted state and restart the ring(s) */
+		/* Clear our internal halted state */
 		xhci->devs[slot_id]->eps[ep_index].ep_state &= ~EP_HALTED;
-		ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
 	}
 }

--
1.9.1