drm/amdgpu: set preferred_domain independent of fallback handling

When GEM needs to fallback to GTT for VRAM BOs we still want the
preferred domain to be untouched so that the BO has a cance to move back
to VRAM in the future.
Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c

@@ -62,6 +62,7 @@ int amdgpu_gem_object_create(struct amdgpu_device *adev, unsigned long size,
 	bp.byte_align = alignment;
 	bp.type = type;
 	bp.resv = resv;
+	bp.preferred_domain = initial_domain;
 retry:
 	bp.flags = flags;
 	bp.domain = initial_domain;

drivers/gpu/drm/amd/amdgpu/amdgpu_object.c

@@ -360,6 +360,7 @@ static int amdgpu_bo_do_create(struct amdgpu_device *adev,
 	};
 	struct amdgpu_bo *bo;
 	unsigned long page_align, size = bp->size;
+	u32 preferred_domains;
 	size_t acc_size;
 	int r;
 
@@ -380,12 +381,14 @@ static int amdgpu_bo_do_create(struct amdgpu_device *adev,
 	drm_gem_private_object_init(adev->ddev, &bo->gem_base, size);
 	INIT_LIST_HEAD(&bo->shadow_list);
 	INIT_LIST_HEAD(&bo->va);
-	bo->preferred_domains = bp->domain & (AMDGPU_GEM_DOMAIN_VRAM |
-					      AMDGPU_GEM_DOMAIN_GTT |
-					      AMDGPU_GEM_DOMAIN_CPU |
-					      AMDGPU_GEM_DOMAIN_GDS |
-					      AMDGPU_GEM_DOMAIN_GWS |
-					      AMDGPU_GEM_DOMAIN_OA);
+	preferred_domains = bp->preferred_domain ? bp->preferred_domain :
+		bp->domain;
+	bo->preferred_domains = preferred_domains & (AMDGPU_GEM_DOMAIN_VRAM |
+						     AMDGPU_GEM_DOMAIN_GTT |
+						     AMDGPU_GEM_DOMAIN_CPU |
+						     AMDGPU_GEM_DOMAIN_GDS |
+						     AMDGPU_GEM_DOMAIN_GWS |
+						     AMDGPU_GEM_DOMAIN_OA);
 	bo->allowed_domains = bo->preferred_domains;
 	if (bp->type != ttm_bo_type_kernel &&
 	    bo->allowed_domains == AMDGPU_GEM_DOMAIN_VRAM)

drivers/gpu/drm/amd/amdgpu/amdgpu_object.h

@@ -37,6 +37,7 @@ struct amdgpu_bo_param {
 	unsigned long			size;
 	int				byte_align;
 	u32				domain;
+	u32				preferred_domain;
 	u64				flags;
 	enum ttm_bo_type		type;
 	struct reservation_object	*resv;