diff options
Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml')
| -rw-r--r-- | Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml | 111 |
1 files changed, 3 insertions, 108 deletions
diff --git a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml index d7c9365ecdbe..d0332f610929 100644 --- a/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml +++ b/Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml @@ -60,7 +60,9 @@ <row> <entry>__u32</entry> <entry><structfield>type</structfield></entry> - <entry>Type of the event.</entry> + <entry>Type of the event, see <xref linkend="event-type" />. Note that +<constant>V4L2_EVENT_ALL</constant> can be used with VIDIOC_UNSUBSCRIBE_EVENT +for unsubscribing all events at once.</entry> </row> <row> <entry>__u32</entry> @@ -84,113 +86,6 @@ </tgroup> </table> - <table frame="none" pgwide="1" id="event-type"> - <title>Event Types</title> - <tgroup cols="3"> - &cs-def; - <tbody valign="top"> - <row> - <entry><constant>V4L2_EVENT_ALL</constant></entry> - <entry>0</entry> - <entry>All events. V4L2_EVENT_ALL is valid only for - VIDIOC_UNSUBSCRIBE_EVENT for unsubscribing all events at once. - </entry> - </row> - <row> - <entry><constant>V4L2_EVENT_VSYNC</constant></entry> - <entry>1</entry> - <entry>This event is triggered on the vertical sync. - This event has a &v4l2-event-vsync; associated with it. - </entry> - </row> - <row> - <entry><constant>V4L2_EVENT_EOS</constant></entry> - <entry>2</entry> - <entry>This event is triggered when the end of a stream is reached. - This is typically used with MPEG decoders to report to the application - when the last of the MPEG stream has been decoded. - </entry> - </row> - <row> - <entry><constant>V4L2_EVENT_CTRL</constant></entry> - <entry>3</entry> - <entry><para>This event requires that the <structfield>id</structfield> - matches the control ID from which you want to receive events. - This event is triggered if the control's value changes, if a - button control is pressed or if the control's flags change. - This event has a &v4l2-event-ctrl; associated with it. This struct - contains much of the same information as &v4l2-queryctrl; and - &v4l2-control;.</para> - - <para>If the event is generated due to a call to &VIDIOC-S-CTRL; or - &VIDIOC-S-EXT-CTRLS;, then the event will <emphasis>not</emphasis> be sent to - the file handle that called the ioctl function. This prevents - nasty feedback loops. If you <emphasis>do</emphasis> want to get the - event, then set the <constant>V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK</constant> - flag. - </para> - - <para>This event type will ensure that no information is lost when - more events are raised than there is room internally. In that - case the &v4l2-event-ctrl; of the second-oldest event is kept, - but the <structfield>changes</structfield> field of the - second-oldest event is ORed with the <structfield>changes</structfield> - 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_SOURCE_CHANGE</constant></entry> - <entry>5</entry> - <entry> - <para>This event is triggered when a source parameter change is - detected during runtime by the video device. It can be a - runtime resolution change triggered by a video decoder or the - format change happening on an input connector. - This event requires that the <structfield>id</structfield> - matches the input index (when used with a video device node) - or the pad index (when used with a subdevice node) from which - you want to receive events.</para> - - <para>This event has a &v4l2-event-src-change; associated - with it. The <structfield>changes</structfield> bitfield denotes - what has changed for the subscribed pad. If multiple events - occurred before application could dequeue them, then the changes - will have the ORed value of all the events generated.</para> - </entry> - </row> - <row> - <entry><constant>V4L2_EVENT_MOTION_DET</constant></entry> - <entry>6</entry> - <entry> - <para>Triggered whenever the motion detection state for one or more of the regions - changes. This event has a &v4l2-event-motion-det; associated with it.</para> - </entry> - </row> - <row> - <entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry> - <entry>0x08000000</entry> - <entry>Base event number for driver-private events.</entry> - </row> - </tbody> - </tgroup> - </table> - <table pgwide="1" frame="none" id="event-flags"> <title>Event Flags</title> <tgroup cols="3"> |