[3.16.y-ckt stable] Patch "usb: xhci: apply XHCI_AVOID_BEI quirk to all Intel xHCI controllers" has been added to staging queue

[Luis Henriques]

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

    usb: xhci: apply XHCI_AVOID_BEI quirk to all Intel xHCI controllers

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?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt10.

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 4c42b16f3e6d52ad65638c25f56ceca60a422589 Mon Sep 17 00:00:00 2001
From: Lu Baolu <baolu.lu at linux.intel.com>
Date: Mon, 23 Mar 2015 18:27:42 +0200
Subject: usb: xhci: apply XHCI_AVOID_BEI quirk to all Intel xHCI controllers

commit 227a4fd801c8a9fa2c4700ab98ec1aec06e3b44d upstream.

When a device with an isochronous endpoint is plugged into the Intel
xHCI host controller, and the driver submits multiple frames per URB,
the xHCI driver will set the Block Event Interrupt (BEI) flag on all
but the last TD for the URB. This causes the host controller to place
an event on the event ring, but not send an interrupt. When the last
TD for the URB completes, BEI is cleared, and we get an interrupt for
the whole URB.

However, under Intel xHCI host controllers, if the event ring is full
of events from transfers with BEI set,  an "Event Ring is Full" event
will be posted to the last entry of the event ring,  but no interrupt
is generated. Host will cease all transfer and command executions and
wait until software completes handling the pending events in the event
ring.  That means xHC stops, but event of "event ring is full" is not
notified. As the result, the xHC looks like dead to user.

This patch is to apply XHCI_AVOID_BEI quirk to Intel xHC devices. And
it should be backported to kernels as old as 3.0, that contains the
commit 69e848c2090a ("Intel xhci: Support EHCI/xHCI port switching.").

Signed-off-by: Lu Baolu <baolu.lu at linux.intel.com>
Tested-by: Alistair Grant <akgrant0710 at gmail.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: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/host/xhci-pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c
index c947bfd260a9..7a68fe1795a5 100644
--- a/drivers/usb/host/xhci-pci.c
+++ b/drivers/usb/host/xhci-pci.c
@@ -113,6 +113,7 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL) {
 		xhci->quirks |= XHCI_LPM_SUPPORT;
 		xhci->quirks |= XHCI_INTEL_HOST;
+		xhci->quirks |= XHCI_AVOID_BEI;
 	}
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
 			pdev->device == PCI_DEVICE_ID_INTEL_PANTHERPOINT_XHCI) {
@@ -128,7 +129,6 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci)
 		 * PPT chipsets.
 		 */
 		xhci->quirks |= XHCI_SPURIOUS_REBOOT;
-		xhci->quirks |= XHCI_AVOID_BEI;
 	}
 	if (pdev->vendor == PCI_VENDOR_ID_INTEL &&
 		pdev->device == PCI_DEVICE_ID_INTEL_LYNXPOINT_LP_XHCI) {