Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/kernel/Documentation/DocBook/media/v4l/dev-event.xml b/kernel/Documentation/DocBook/media/v4l/dev-event.xml
new file mode 100644
index 000000000..19f4becfa
--- /dev/null
+++ b/kernel/Documentation/DocBook/media/v4l/dev-event.xml
@@ -0,0 +1,43 @@
+  <title>Event Interface</title>
+
+  <para>The V4L2 event interface provides a means for a 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. Changes in the value or state of a V4L2 control can also be
+  reported through events.
+  </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>
+
+  <para>Starting with kernel 3.1 certain guarantees can be given with
+  regards to events:<orderedlist>
+	<listitem>
+	  <para>Each subscribed event has its own internal dedicated event queue.
+This means that flooding of one event type will not interfere with other
+event types.</para>
+	</listitem>
+	<listitem>
+	  <para>If the internal event queue for a particular subscribed event
+becomes full, then the oldest event in that queue will be dropped.</para>
+	</listitem>
+	<listitem>
+	  <para>Where applicable, certain event types can ensure that the payload
+of the oldest event that is about to be dropped will be merged with the payload
+of the next oldest event. Thus ensuring that no information is lost, but only an
+intermediate step leading up to that information. See the documentation for the
+event you want to subscribe to whether this is applicable for that event or not.</para>
+	</listitem>
+      </orderedlist></para>