From 2de43a0164ba5364ffd7cb48f0bccc9873e87332 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri, 18 Jan 2013 12:01:54 +0000
Subject: [PATCH] sna: Skip an empty slave update

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 src/sna/sna_accel.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/sna/sna_accel.c b/src/sna/sna_accel.c
index ed13569d..99063de1 100644
--- a/src/sna/sna_accel.c
+++ b/src/sna/sna_accel.c
@@ -13821,6 +13821,9 @@ static void sna_accel_post_damage(struct sna *sna)
 		     region.extents.x2, region.extents.y2));
 
 		RegionIntersect(&region, &region, damage);
+		if (!RegionNotEmpty(&region))
+			continue;
+
 		RegionTranslate(&region, -dirty->x, -dirty->y);
 		DamageRegionAppend(&dirty->slave_dst->drawable, &region);