From 16e10490d260493cec30c5e7adacf99ba304d8b9 Mon Sep 17 00:00:00 2001
From: Ben Skeggs <bskeggs@redhat.com>
Date: Thu, 11 May 2017 16:53:42 +1000
Subject: drm/nouveau/tmr: ack interrupt before processing alarms

commit 3733bd8b407211739e72d051e5f30ad82a52c4bc upstream.

Fixes a race where we can miss an alarm that triggers while we're already
processing previous alarms.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/nv04.c b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/nv04.c
index 7b9ce87..7f48249 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/timer/nv04.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/timer/nv04.c
@@ -76,8 +76,8 @@ nv04_timer_intr(struct nvkm_timer *tmr)
 	u32 stat = nvkm_rd32(device, NV04_PTIMER_INTR_0);
 
 	if (stat & 0x00000001) {
-		nvkm_timer_alarm_trigger(tmr);
 		nvkm_wr32(device, NV04_PTIMER_INTR_0, 0x00000001);
+		nvkm_timer_alarm_trigger(tmr);
 		stat &= ~0x00000001;
 	}
 
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