1 files changed, 4 insertions, 1 deletions

diff --git a/include/media/bt819.h b/include/media/bt819.h
index 38f666bde77a..8025f4bc2bb6 100644
--- a/include/media/bt819.h
+++ b/include/media/bt819.h
@@ -26,7 +26,10 @@
 /* v4l2_device notifications. */
 
 /* Needed to reset the FIFO buffer when changing the input
-   or the video standard. */
+   or the video standard.
+
+   Note: these ioctls that internal to the kernel and are never called
+   from userspace. */
 #define BT819_FIFO_RESET_LOW    _IO('b', 0)
 #define BT819_FIFO_RESET_HIGH   _IO('b', 1)