From c5244987394648913ae1a03879c58058a2fc2cee Mon Sep 17 00:00:00 2001
From: Oded Gabbay <oded.gabbay@gmail.com>
Date: Sat, 30 Jan 2016 07:59:33 +0200
Subject: [PATCH] drm/radeon: mask out WC from BO on unsupported arches
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Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
---
 drivers/gpu/drm/radeon/radeon_object.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index 84d45633d28c..fb6ad143873f 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -33,6 +33,7 @@
 #include <linux/slab.h>
 #include <drm/drmP.h>
 #include <drm/radeon_drm.h>
+#include <drm/drm_cache.h>
 #include "radeon.h"
 #include "radeon_trace.h"
 
@@ -245,6 +246,12 @@ int radeon_bo_create(struct radeon_device *rdev,
 		DRM_INFO_ONCE("Please enable CONFIG_MTRR and CONFIG_X86_PAT for "
 			      "better performance thanks to write-combining\n");
 	bo->flags &= ~(RADEON_GEM_GTT_WC | RADEON_GEM_GTT_UC);
+#else
+	/* For architectures that don't support WC memory,
+	 * mask out the WC flag from the BO
+	 */
+	if (!drm_arch_can_wc_memory())
+		bo->flags &= ~RADEON_GEM_GTT_WC;
 #endif
 
 	radeon_ttm_placement_from_domain(bo, domain);
-- 
2.39.5