From eab00a0da292fa7118aaf20da78e834866de00ae Mon Sep 17 00:00:00 2001
From: Sakari Ailus <sakari.ailus@iki.fi>
Date: Mon, 18 Jul 2011 08:40:03 -0300
Subject: [media] v4l: events: Define V4L2_EVENT_FRAME_SYNC

Define a frame sync event to tell user space when the reception of a frame
starts.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
---
 Documentation/DocBook/media/v4l/vidioc-dqevent.xml | 22 ++++++++++++++++++++++
 .../DocBook/media/v4l/vidioc-subscribe-event.xml   | 16 ++++++++++++++++
 2 files changed, 38 insertions(+)

(limited to 'Documentation/DocBook')

diff --git a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
index 5200b6874654..e8714aa16433 100644
--- a/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-dqevent.xml
@@ -86,6 +86,12 @@
 	    <entry>Event data for event V4L2_EVENT_CTRL.
             </entry>
 	  </row>
+	  <row>
+	    <entry></entry>
+	    <entry>&v4l2-event-frame-sync;</entry>
+            <entry><structfield>frame</structfield></entry>
+	    <entry>Event data for event V4L2_EVENT_FRAME_SYNC.</entry>
+	  </row>
 	  <row>
 	    <entry></entry>
 	    <entry>__u8</entry>
@@ -220,6 +226,22 @@
       </tgroup>
     </table>
 
+    <table frame="none" pgwide="1" id="v4l2-event-frame-sync">
+      <title>struct <structname>v4l2_event_frame_sync</structname></title>
+      <tgroup cols="3">
+	&cs-str;
+	<tbody valign="top">
+	  <row>
+	    <entry>__u32</entry>
+	    <entry><structfield>frame_sequence</structfield></entry>
+	    <entry>
+	      The sequence number of the frame being received.
+	    </entry>
+	  </row>
+	</tbody>
+      </tgroup>
+    </table>
+
     <table pgwide="1" frame="none" id="changes-flags">
       <title>Changes</title>
       <tgroup cols="3">
diff --git a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
index 275be9689d88..5c70b616d818 100644
--- a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
@@ -138,6 +138,22 @@
 		field of the oldest event.</para>
 	    </entry>
 	  </row>
+	  <row>
+	    <entry><constant>V4L2_EVENT_FRAME_SYNC</constant></entry>
+	    <entry>4</entry>
+	    <entry>
+	      <para>Triggered immediately when the reception of a
+	      frame has begun. This event has a
+	      &v4l2-event-frame-sync; associated with it.</para>
+
+	      <para>If the hardware needs to be stopped in the case of a
+	      buffer underrun it might not be able to generate this event.
+	      In such cases the <structfield>frame_sequence</structfield>
+	      field in &v4l2-event-frame-sync; will not be incremented. This
+	      causes two consecutive frame sequence numbers to have n times
+	      frame interval in between them.</para>
+	    </entry>
+	  </row>
 	  <row>
 	    <entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry>
 	    <entry>0x08000000</entry>
-- 
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