drm/radeon/rv740: fix backend setup

This patch fixes occlusion queries and rendering errors
on rv740 boards. Hardcoding the backend map is not an optimal
solution, but a better fix is being worked on.
Signed-off-by: NAlex Deucher <alexdeucher@gmail.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/r600_cp.c

@@ -1428,9 +1428,12 @@ static void r700_gfx_init(struct drm_device *dev,
 
 	gb_tiling_config |= R600_BANK_SWAPS(1);
 
-	backend_map = r700_get_tile_pipe_to_backend_map(dev_priv->r600_max_tile_pipes,
-							dev_priv->r600_max_backends,
-							(0xff << dev_priv->r600_max_backends) & 0xff);
+	if ((dev_priv->flags & RADEON_FAMILY_MASK) == CHIP_RV740)
+		backend_map = 0x28;
+	else
+		backend_map = r700_get_tile_pipe_to_backend_map(dev_priv->r600_max_tile_pipes,
+								dev_priv->r600_max_backends,
+								(0xff << dev_priv->r600_max_backends) & 0xff);
 	gb_tiling_config |= R600_BACKEND_MAP(backend_map);
 
 	cc_gc_shader_pipe_config =

drivers/gpu/drm/radeon/rv770.c

@@ -549,9 +549,12 @@ static void rv770_gpu_init(struct radeon_device *rdev)
 
 	gb_tiling_config |= BANK_SWAPS(1);
 
-	backend_map = r700_get_tile_pipe_to_backend_map(rdev->config.rv770.max_tile_pipes,
-							rdev->config.rv770.max_backends,
-							(0xff << rdev->config.rv770.max_backends) & 0xff);
+	if (rdev->family == CHIP_RV740)
+		backend_map = 0x28;
+	else
+		backend_map = r700_get_tile_pipe_to_backend_map(rdev->config.rv770.max_tile_pipes,
+								rdev->config.rv770.max_backends,
+								(0xff << rdev->config.rv770.max_backends) & 0xff);
 	gb_tiling_config |= BACKEND_MAP(backend_map);
 
 	cc_gc_shader_pipe_config =