commit d112bea70d92bc2358a0292b3719b0546c1c1e25
Author: Michel Dänzer <michel.daenzer@amd.com>
Date:   Wed Aug 27 16:11:05 2014 +0900

    drm/radeon: Add RADEON_GEM_CPU_ACCESS BO creation flag

diff --git a/drivers/gpu/drm/radeon/radeon_object.c b/drivers/gpu/drm/radeon/radeon_object.c
index dc74cc5..908ea541 100644
--- a/drivers/gpu/drm/radeon/radeon_object.c
+++ b/drivers/gpu/drm/radeon/radeon_object.c
@@ -143,7 +143,12 @@ void radeon_ttm_placement_from_domain(struct radeon_bo *rbo, u32 domain)
 
 	for (i = 0; i < c; ++i) {
 		rbo->placements[i].fpfn = 0;
-		rbo->placements[i].lpfn = 0;
+		if ((rbo->flags & RADEON_GEM_CPU_ACCESS) &&
+		    (rbo->placements[i].flags & TTM_PL_FLAG_VRAM))
+			rbo->placements[i].lpfn =
+				rbo->rdev->mc.visible_vram_size >> PAGE_SHIFT;
+		else
+			rbo->placements[i].lpfn = 0;
 	}
 
 	/*
@@ -151,7 +156,9 @@ void radeon_ttm_placement_from_domain(struct radeon_bo *rbo, u32 domain)
 	 * improve fragmentation quality.
 	 * 512kb was measured as the most optimal number.
 	 */
-	if (rbo->tbo.mem.size > 512 * 1024) {
+	if (!((rbo->flags & RADEON_GEM_CPU_ACCESS) &&
+	      (rbo->placements[i].flags & TTM_PL_FLAG_VRAM)) &&
+	    rbo->tbo.mem.size > 512 * 1024) {
 		for (i = 0; i < c; i++) {
 			rbo->placements[i].flags |= TTM_PL_FLAG_TOPDOWN;
 		}
diff --git a/include/uapi/drm/radeon_drm.h b/include/uapi/drm/radeon_drm.h
index 509b2d7..bf0067b 100644
--- a/include/uapi/drm/radeon_drm.h
+++ b/include/uapi/drm/radeon_drm.h
@@ -799,6 +799,8 @@ struct drm_radeon_gem_info {
 #define RADEON_GEM_NO_BACKING_STORE	(1 << 0)
 #define RADEON_GEM_GTT_UC		(1 << 1)
 #define RADEON_GEM_GTT_WC		(1 << 2)
+/* BO is expected to be accessed by the CPU */
+#define RADEON_GEM_CPU_ACCESS		(1 << 3)
 
 struct drm_radeon_gem_create {
 	uint64_t	size;