From: Jason Wang <jasowang@redhat.com>
Date: Mon, 12 May 2014 08:35:39 +0000 (+0800)
Subject: drm/qxl: return IRQ_NONE if it was not our irq
X-Git-Tag: firefly_0821_release~3679^2~1761
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1ed9cbc93c613efa69df58a1d4c8037adb105f43;p=firefly-linux-kernel-4.4.55.git

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@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpu/drm/qxl/qxl_irq.c b/drivers/gpu/drm/qxl/qxl_irq.c
index 21393dc4700a..f4b6b89b98f3 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) {