drm/radeon: Use write-combined CPU mappings of IBs on >= CIK

Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_ring.c

@@ -201,10 +201,22 @@ int radeon_ib_pool_init(struct radeon_device *rdev)
 	if (rdev->ib_pool_ready) {
 		return 0;
 	}
-	r = radeon_sa_bo_manager_init(rdev, &rdev->ring_tmp_bo,
-				      RADEON_IB_POOL_SIZE*64*1024,
-				      RADEON_GPU_PAGE_SIZE,
-				      RADEON_GEM_DOMAIN_GTT, 0);
+
+	if (rdev->family >= CHIP_BONAIRE) {
+		r = radeon_sa_bo_manager_init(rdev, &rdev->ring_tmp_bo,
+					      RADEON_IB_POOL_SIZE*64*1024,
+					      RADEON_GPU_PAGE_SIZE,
+					      RADEON_GEM_DOMAIN_GTT,
+					      RADEON_GEM_GTT_WC);
+	} else {
+		/* Before CIK, it's better to stick to cacheable GTT due
+		 * to the command stream checking
+		 */
+		r = radeon_sa_bo_manager_init(rdev, &rdev->ring_tmp_bo,
+					      RADEON_IB_POOL_SIZE*64*1024,
+					      RADEON_GPU_PAGE_SIZE,
+					      RADEON_GEM_DOMAIN_GTT, 0);
+	}
 	if (r) {
 		return r;
 	}