[media] DocBook/media: improve timestamp documentation

Explain which clock was used to make the timestamp.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
index 50ccd33948c1cbee6fb8bbd28864681780c1b833..c9c3c7713832931954b12d58ff4bfb3c6fa4afb3 100644 (file)
--- a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
@@ -133,7 +133,10 @@
            <entry>struct timespec</entry>
            <entry><structfield>timestamp</structfield></entry>
             <entry></entry>
-           <entry>Event timestamp.</entry>
+           <entry>Event timestamp. The timestamp has been taken from the
+           <constant>CLOCK_MONOTONIC</constant> clock. To access the
+           same clock outside V4L2, use <function>clock_gettime(2)</function>.
+           </entry>
          </row>
          <row>
            <entry>u32</entry>