diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index 4c4e0f8375b3..e3f1b4a4b601 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -908,7 +908,7 @@ extern int ttm_bo_move_accel_cleanup(struct ttm_buffer_object *bo,
  * Utility function that returns the pgprot_t that should be used for
  * setting up a PTE with the caching model indicated by @c_state.
  */
-extern pgprot_t ttm_io_prot(enum ttm_caching_state c_state, pgprot_t tmp);
+extern pgprot_t ttm_io_prot(uint32_t caching_flags, pgprot_t tmp);
 
 #if (defined(CONFIG_AGP) || (defined(CONFIG_AGP_MODULE) && defined(MODULE)))
 #define TTM_HAS_AGP