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[media] V4L2 spec: document control events

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Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2011-06-07 09:53:37 -03:00 committed by Mauro Carvalho Chehab
parent ce7275747b
commit 85724983c4
2 changed files with 157 additions and 2 deletions
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17
Documentation/DocBook/media/v4l/vidioc-dqevent.xml
View file

@ -79,6 +79,13 @@
<entry>Event data for event V4L2_EVENT_VSYNC.
</entry>
</row>
<row>
<entry></entry>
<entry>&v4l2-event-ctrl;</entry>
<entry><structfield>ctrl</structfield></entry>
<entry>Event data for event V4L2_EVENT_CTRL.
</entry>
</row>
<row>
<entry></entry>
<entry>__u8</entry>
@ -109,9 +116,17 @@
<entry></entry>
<entry>Event timestamp.</entry>
</row>
<row>
<entry>u32</entry>
<entry><structfield>id</structfield></entry>
<entry></entry>
<entry>The ID associated with the event source. If the event does not
have an associated ID (this depends on the event type), then this
is 0.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[9]</entry>
<entry><structfield>reserved</structfield>[8]</entry>
<entry></entry>
<entry>Reserved for future extensions. Drivers must set
the array to zero.</entry>

142
Documentation/DocBook/media/v4l/vidioc-subscribe-event.xml
View file

@ -64,7 +64,19 @@
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[7]</entry>
<entry><structfield>id</structfield></entry>
<entry>ID of the event source. If there is no ID associated with
the event source, then set this to 0. Whether or not an event
needs an ID depends on the event type.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>flags</structfield></entry>
<entry>Event flags, see <xref linkend="event-flags" />.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>reserved</structfield>[5]</entry>
<entry>Reserved for future extensions. Drivers and applications
must set the array to zero.</entry>
</row>
@ -99,6 +111,23 @@
when the last of the MPEG stream has been decoded.
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_CTRL</constant></entry>
<entry>3</entry>
<entry>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 &v4l2-event-ctrl; associated with it. This struct
contains much of the same information as &v4l2-queryctrl; and
&v4l2-control;.
If the event is generated due to a call to &VIDIOC-S-CTRL; or
&VIDIOC-S-EXT-CTRLS;, then the event will not be sent to
the file handle that called the ioctl function. This prevents
nasty feedback loops.
</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_PRIVATE_START</constant></entry>
<entry>0x08000000</entry>
@ -108,6 +137,23 @@
</tgroup>
</table>
<table pgwide="1" frame="none" id="event-flags">
<title>Event Flags</title>
<tgroup cols="3">
&cs-def;
<tbody valign="top">
<row>
<entry><constant>V4L2_EVENT_SUB_FL_SEND_INITIAL</constant></entry>
<entry>0x0001</entry>
<entry>When this event is subscribed an initial event will be sent
containing the current status. This only makes sense for events
that are triggered by a status change. Other events will ignore
this flag.</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">
@ -122,6 +168,100 @@
</tgroup>
</table>
<table frame="none" pgwide="1" id="v4l2-event-ctrl">
<title>struct <structname>v4l2_event_ctrl</structname></title>
<tgroup cols="4">
&cs-str;
<tbody valign="top">
<row>
<entry>__u32</entry>
<entry><structfield>changes</structfield></entry>
<entry></entry>
<entry>A bitmask that tells what has changed. See <xref linkend="changes-flags" />.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>type</structfield></entry>
<entry></entry>
<entry>The type of the control. See &v4l2-ctrl-type;.</entry>
</row>
<row>
<entry>union (anonymous)</entry>
<entry></entry>
<entry></entry>
<entry></entry>
</row>
<row>
<entry></entry>
<entry>__s32</entry>
<entry><structfield>value</structfield></entry>
<entry>The 32-bit value of the control for 32-bit control types.
This is 0 for string controls since the value of a string
cannot be passed using &VIDIOC-DQEVENT;.</entry>
</row>
<row>
<entry></entry>
<entry>__s64</entry>
<entry><structfield>value64</structfield></entry>
<entry>The 64-bit value of the control for 64-bit control types.</entry>
</row>
<row>
<entry>__u32</entry>
<entry><structfield>flags</structfield></entry>
<entry></entry>
<entry>The control flags. See <xref linkend="control-flags" />.</entry>
</row>
<row>
<entry>__s32</entry>
<entry><structfield>minimum</structfield></entry>
<entry></entry>
<entry>The minimum value of the control. See &v4l2-queryctrl;.</entry>
</row>
<row>
<entry>__s32</entry>
<entry><structfield>maximum</structfield></entry>
<entry></entry>
<entry>The maximum value of the control. See &v4l2-queryctrl;.</entry>
</row>
<row>
<entry>__s32</entry>
<entry><structfield>step</structfield></entry>
<entry></entry>
<entry>The step value of the control. See &v4l2-queryctrl;.</entry>
</row>
<row>
<entry>__s32</entry>
<entry><structfield>default_value</structfield></entry>
<entry></entry>
<entry>The default value value of the control. See &v4l2-queryctrl;.</entry>
</row>
</tbody>
</tgroup>
</table>
<table pgwide="1" frame="none" id="changes-flags">
<title>Changes</title>
<tgroup cols="3">
&cs-def;
<tbody valign="top">
<row>
<entry><constant>V4L2_EVENT_CTRL_CH_VALUE</constant></entry>
<entry>0x0001</entry>
<entry>This control event was triggered because the value of the control
changed. Special case: if a button control is pressed, then this
event is sent as well, even though there is not explicit value
associated with a button control.</entry>
</row>
<row>
<entry><constant>V4L2_EVENT_CTRL_CH_FLAGS</constant></entry>
<entry>0x0002</entry>
<entry>This control event was triggered because the control flags
changed.</entry>
</row>
</tbody>
</tgroup>
</table>
</refsect1>
</refentry>
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