drm: Document that drm_dev_alloc doesn't need a parent
Possible for purely virtual debug devices.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 2e5c7d9..4f41377 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -535,6 +535,8 @@
* The initial ref-count of the object is 1. Use drm_dev_ref() and
* drm_dev_unref() to take and drop further ref-counts.
*
+ * Note that for purely virtual devices @parent can be NULL.
+ *
* RETURNS:
* Pointer to new DRM device, or NULL if out of memory.
*/