openwrt/target/linux/brcm2708/patches-4.4/0099-drm-vc4-Remove-extra-barrier-s-aroudn-CTnCA-CTnEA-se.patch

From 77d99c047cae1413a2a5f2aa2f0a0723388d9e7b Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Fri, 23 Oct 2015 12:33:43 +0100
Subject: [PATCH] drm/vc4: Remove extra barrier()s aroudn CTnCA/CTnEA setup.

The writel() that these expand to already does barriers.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/vc4/vc4_gem.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/vc4/vc4_gem.c
+++ b/drivers/gpu/drm/vc4/vc4_gem.c
@@ -104,14 +104,11 @@ submit_cl(struct drm_device *dev, uint32
 {
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 
-	V3D_WRITE(V3D_CTNCA(thread), start);
-	barrier();
-
-	/* Set the end address of the control list.  Writing this
-	 * register is what starts the job.
+	/* Set the current and end address of the control list.
+	 * Writing the end register is what starts the job.
 	 */
+	V3D_WRITE(V3D_CTNCA(thread), start);
 	V3D_WRITE(V3D_CTNEA(thread), end);
-	barrier();
 }
 
 int