diff --git a/Documentation/gpu/drm-mm.rst b/Documentation/gpu/drm-mm.rst
index 66d24b745c62..1c9930fb5e7d 100644
--- a/Documentation/gpu/drm-mm.rst
+++ b/Documentation/gpu/drm-mm.rst
@@ -43,6 +43,12 @@ TTM device object reference
 .. kernel-doc:: drivers/gpu/drm/ttm/ttm_device.c
    :export:
 
+TTM resource placement reference
+--------------------------------
+
+.. kernel-doc:: include/drm/ttm/ttm_placement.h
+   :internal:
+
 TTM resource object reference
 -----------------------------
 
diff --git a/include/drm/ttm/ttm_placement.h b/include/drm/ttm/ttm_placement.h
index 8995c9e4ec1b..76d1b9119a2b 100644
--- a/include/drm/ttm/ttm_placement.h
+++ b/include/drm/ttm/ttm_placement.h
@@ -58,6 +58,7 @@
  *
  * @fpfn:	first valid page frame number to put the object
  * @lpfn:	last valid page frame number to put the object
+ * @mem_type:	One of TTM_PL_* where the resource should be allocated from.
  * @flags:	memory domain and caching flags for the object
  *
  * Structure indicating a possible place to put an object.