[3.13.y.z extended stable] Patch "drm/qxl: return IRQ_NONE if it was not our irq" has been added to staging queue

[Kamal Mostafa]

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

    drm/qxl: return IRQ_NONE if it was not our irq

to the linux-3.13.y-queue branch of the 3.13.y.z 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 3.13.11.6.

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.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 929cc94e589032dbc5fbfd79bcc5e061fca0a556 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang at redhat.com>
Date: Mon, 12 May 2014 16:35:39 +0800
Subject: drm/qxl: return IRQ_NONE if it was not our irq

commit fbb60fe35ad579b511de8604b06a30b43846473b upstream.

Return IRQ_NONE if it was not our irq. This is necessary for the case
when qxl is sharing irq line with a device A in a crash kernel. If qxl
is initialized before A and A's irq was raised during this gap,
returning IRQ_HANDLED in this case will cause this irq to be raised
again after EOI since kernel think it was handled but in fact it was
not.

Cc: Gerd Hoffmann <kraxel at redhat.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
Signed-off-by: Dave Airlie <airlied at redhat.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/gpu/drm/qxl/qxl_irq.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/qxl/qxl_irq.c b/drivers/gpu/drm/qxl/qxl_irq.c
index 21393dc..f4b6b89 100644
--- a/drivers/gpu/drm/qxl/qxl_irq.c
+++ b/drivers/gpu/drm/qxl/qxl_irq.c
@@ -33,6 +33,9 @@ irqreturn_t qxl_irq_handler(DRM_IRQ_ARGS)

 	pending = xchg(&qdev->ram_header->int_pending, 0);

+	if (!pending)
+		return IRQ_NONE;
+
 	atomic_inc(&qdev->irq_received);

 	if (pending & QXL_INTERRUPT_DISPLAY) {
--
1.9.1