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+  <title>Event Interface</title>
+
+  <para>The V4L2 event interface provides means for user to get
+  immediately notified on certain conditions taking place on a device.
+  This might include start of frame or loss of signal events, for
+  example.
+  </para>
+
+  <para>To receive events, the events the user is interested in first must
+  be subscribed using the &VIDIOC-SUBSCRIBE-EVENT; ioctl. Once an event is
+  subscribed, the events of subscribed types are dequeueable using the
+  &VIDIOC-DQEVENT; ioctl. Events may be unsubscribed using
+  VIDIOC_UNSUBSCRIBE_EVENT ioctl. The special event type V4L2_EVENT_ALL may
+  be used to unsubscribe all the events the driver supports.</para>
+
+  <para>The event subscriptions and event queues are specific to file
+  handles. Subscribing an event on one file handle does not affect
+  other file handles.
+  </para>
+
+  <para>The information on dequeueable events is obtained by using select or
+  poll system calls on video devices. The V4L2 events use POLLPRI events on
+  poll system call and exceptions on select system call.  </para>
+
+  <!--
+Local Variables:
+mode: sgml
+sgml-parent-document: "v4l2.sgml"
+indent-tabs-mode: nil
+End:
+  -->