[PATCH 3.15 087/109] drm/qxl: return IRQ_NONE if it was not our irq

Greg Kroah-Hartman
2014-07-26T19:02:49Z

From: Jason Wang <jasowang@redhat.com>

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>

---
drivers/gpu/drm/qxl/qxl_irq.c | 3 +++
1 file changed, 3 insertions(+)

--- 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(int irq, voi

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

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

if (pending & QXL_INTERRUPT_DISPLAY) {