[PATCH 4.2.y-ckt 062/273] drm/radeon: mask out WC from BO on unsupported arches

[Kamal Mostafa]

4.2.8-ckt5 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Oded Gabbay <oded.gabbay at gmail.com>

commit c5244987394648913ae1a03879c58058a2fc2cee upstream.

Reviewed-by: Christian König <christian.koenig at amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay at gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 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 6e88c1b0..06c3135 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"
 
@@ -244,6 +245,12 @@ 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;
+#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);
-- 
2.7.0