</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>
<entry><constant>V4L2_EVENT_VSYNC</constant></entry>
<entry>1</entry>
<entry>This event is triggered on the vertical sync.
- This event has &v4l2-event-vsync; associated with it.
+ This event has a &v4l2-event-vsync; associated with it.
</entry>
</row>
<row>
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_PRIVATE_START</constant></entry>
<entry>0x08000000</entry>
</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 such as <constant>V4L2_EVENT_CTRL</constant>.
+ Other events will ignore this flag.</entry>
+ </row>
+ <row>
+ <entry><constant>V4L2_EVENT_SUB_FL_ALLOW_FEEDBACK</constant></entry>
+ <entry>0x0002</entry>
+ <entry><para>If set, then events directly caused by an ioctl will also be sent to
+ the filehandle that called that ioctl. For example, changing a control using
+ &VIDIOC-S-CTRL; will cause a V4L2_EVENT_CTRL to be sent back to that same
+ filehandle. Normally such events are suppressed to prevent feedback loops
+ where an application changes a control to a one value and then another, and
+ then receives an event telling it that that control has changed to the first
+ value.</para>
+
+ <para>Since it can't tell whether that event was caused by another application
+ or by the &VIDIOC-S-CTRL; call it is hard to decide whether to set the
+ control to the value in the event, or ignore it.</para>
+
+ <para>Think carefully when you set this flag so you won't get into situations
+ like that.</para>
+ </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">
</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>
+ <refsect1>
+ &return-value;
</refsect1>
</refentry>
-<!--
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-mode: sgml
-sgml-parent-document: "v4l2.sgml"
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git.openpandora.org / pandora-kernel.git / blobdiff