V4L/DVB (5419): Add comment how the speed field is interpreted.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/dvb/video.h b/include/linux/dvb/video.h
index 4c314914339f..93e4c3a6d190 100644
--- a/include/linux/dvb/video.h
+++ b/include/linux/dvb/video.h
@@ -110,6 +110,11 @@ struct video_command {
                 } stop;
 
                 struct {
+                        /* 0 or 1000 specifies normal speed,
+                           1 specifies forward single stepping,
+                           -1 specifies backward single stepping,
+                           >1: playback at speed/1000 of the normal speed,
+                           <-1: reverse playback at (-speed/1000) of the normal speed. */
                         __s32 speed;
                         __u32 format;
                 } play;