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[media] DocBook media: improve event documentation 

It always annoyed me that the event type documentation was separate from the struct
v4l2_event documentation. This patch moves it all to one place, VIDIOC_DQEVENT.

This makes much more sense.

Also changed the 'changes-flags' ref to 'ctrl-changes-flags' since this referred to
control changes. There is a src-changes-flags as well, so 'changes-flags' was a bit
vague.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
This commit is contained in:
Hans Verkuil 2015-03-18 07:05:31 -03:00 committed by Mauro Carvalho Chehab
parent 9a68c9fa76
commit b766586b1a
3 changed files with 115 additions and 113 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Documentation/DocBook/media/v4l/compat.xml
View File

@ -2491,7 +2491,7 @@ that used it. It was originally scheduled for removal in 2.6.35.
</listitem>
<listitem>
<para>Added <constant>V4L2_EVENT_CTRL_CH_RANGE</constant> control event
changes flag. See <xref linkend="changes-flags"/>.</para>
changes flag. See <xref linkend="ctrl-changes-flags"/>.</para>
</listitem>
</orderedlist>
</section>

115
Documentation/DocBook/media/v4l/vidioc-dqevent.xml
View File

@ -64,7 +64,7 @@
<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
<entry></entry>
<entry>Type of the event.</entry>
<entry>Type of the event, see <xref linkend="event-type" />.</entry>
</row>
<row>
<entry>union</entry>
@ -154,6 +154,113 @@
</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 frame="none" pgwide="1" id="v4l2-event-vsync">
<title>struct <structname>v4l2_event_vsync</structname></title>
<tgroup cols="3">
@ -177,7 +284,7 @@
<entry>__u32</entry>
<entry><structfield>changes</structfield></entry>
<entry></entry>
<entry>A bitmask that tells what has changed. See <xref linkend="changes-flags" />.</entry>
<entry>A bitmask that tells what has changed. See <xref linkend="ctrl-changes-flags" />.</entry>
</row>
<row>
<entry>__u32</entry>
@ -309,8 +416,8 @@
</tgroup>
</table>
<table pgwide="1" frame="none" id="changes-flags">
<title>Changes</title>
<table pgwide="1" frame="none" id="ctrl-changes-flags">
<title>Control Changes</title>
<tgroup cols="3">
&cs-def;
<tbody valign="top">

111
Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
View File

@ -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">