drm: add more document for drm_crtc_from_index()
Add a bit more document for function drm_crtc_from_index() to cross
link it with drm_crtc_from_index(), and explain that the function is
useful in vblank code.
While at it, add cross link comment for drm_plane_from_index() as well.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1483779131-19935-1-git-send-email-shawnguo@kernel.org
diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
index 7b7275f..eed66be 100644
--- a/drivers/gpu/drm/drm_plane.c
+++ b/drivers/gpu/drm/drm_plane.c
@@ -254,7 +254,7 @@ EXPORT_SYMBOL(drm_plane_cleanup);
* @idx: index of registered plane to find for
*
* Given a plane index, return the registered plane from DRM device's
- * list of planes with matching index.
+ * list of planes with matching index. This is the inverse of drm_plane_index().
*/
struct drm_plane *
drm_plane_from_index(struct drm_device *dev, int idx)