path: root/Documentation/DocBook/media/v4l
diff options
Diffstat (limited to 'Documentation/DocBook/media/v4l')
3 files changed, 25 insertions, 1 deletions
diff --git a/Documentation/DocBook/media/v4l/compat.xml b/Documentation/DocBook/media/v4l/compat.xml
index ce1004a7da5..91410b6e7e0 100644
--- a/Documentation/DocBook/media/v4l/compat.xml
+++ b/Documentation/DocBook/media/v4l/compat.xml
@@ -2370,6 +2370,14 @@ that used it. It was originally scheduled for removal in 2.6.35.
+ <section>
+ <title>V4L2 in Linux 3.2</title>
+ <orderedlist>
+ <listitem>
+ <para>V4L2_CTRL_FLAG_VOLATILE was added to signal volatile controls to userspace.</para>
+ </listitem>
+ </orderedlist>
+ </section>
<section id="other">
<title>Relation of V4L2 to other Linux multimedia APIs</title>
diff --git a/Documentation/DocBook/media/v4l/v4l2.xml b/Documentation/DocBook/media/v4l/v4l2.xml
index 0d05e8747c1..40132c27764 100644
--- a/Documentation/DocBook/media/v4l/v4l2.xml
+++ b/Documentation/DocBook/media/v4l/v4l2.xml
@@ -128,6 +128,13 @@ structs, ioctls) must be noted in more detail in the history chapter
applications. -->
+ <revnumber>3.2</revnumber>
+ <date>2011-08-26</date>
+ <authorinitials>hv</authorinitials>
+ <revremark>Added V4L2_CTRL_FLAG_VOLATILE.</revremark>
+ </revision>
+ <revision>
<authorinitials>mcc, po, hv</authorinitials>
@@ -410,7 +417,7 @@ and discussions on the V4L mailing list.</revremark>
<title>Video for Linux Two API Specification</title>
- <subtitle>Revision 3.1</subtitle>
+ <subtitle>Revision 3.2</subtitle>
<chapter id="common">
diff --git a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml
index 677ea646c29..0ac0057a51c 100644
--- a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml
+++ b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml
@@ -406,6 +406,15 @@ flag is typically present for relative controls or action controls where
writing a value will cause the device to carry out a given action
(&eg; motor control) but no meaningful value can be returned.</entry>
+ <row>
+ <entry><constant>V4L2_CTRL_FLAG_VOLATILE</constant></entry>
+ <entry>0x0080</entry>
+ <entry>This control is volatile, which means that the value of the control
+changes continuously. A typical example would be the current gain value if the device
+is in auto-gain mode. In such a case the hardware calculates the gain value based on
+the lighting conditions which can change over time. Note that setting a new value for
+a volatile control will have no effect. The new value will just be ignored.</entry>
+ </row>