linux/Documentation/DocBook/media/v4l/vidioc-g-output.xml
Mauro Carvalho Chehab 4266129964 [media] DocBook: Move all media docbook stuff into its own directory
This patch addresses several issues pointed by Randy Dunlap
<rdunlap@xenotime.net> at changeset ece722c:

- In the generated index.html file, "media" is listed first, but it
  should be listed in alphabetical order, not first.

- The generated files are (hidden) in .tmpmedia/

- The link from the top-level index.html file to "media" is to
  media/index.html, but the file is actually in .tmpmedia/media/index.html

- Please build docs with and without using "O=builddir" and test that.

- Would it be possible for media to have its own Makefile instead of
  merging into this one?

Due to the way cleandocs target works, I had to rename the media DocBook
to media_api, otherwise cleandocs would remove the /media directory.

Thanks-to: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2011-07-27 17:52:05 -03:00

101 lines
2.7 KiB
XML

<refentry id="vidioc-g-output">
<refmeta>
<refentrytitle>ioctl VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>VIDIOC_G_OUTPUT</refname>
<refname>VIDIOC_S_OUTPUT</refname>
<refpurpose>Query or select the current video output</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>int <function>ioctl</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>request</parameter></paramdef>
<paramdef>int *<parameter>argp</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Arguments</title>
<variablelist>
<varlistentry>
<term><parameter>fd</parameter></term>
<listitem>
<para>&fd;</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>request</parameter></term>
<listitem>
<para>VIDIOC_G_OUTPUT, VIDIOC_S_OUTPUT</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>To query the current video output applications call the
<constant>VIDIOC_G_OUTPUT</constant> ioctl with a pointer to an integer
where the driver stores the number of the output, as in the
&v4l2-output; <structfield>index</structfield> field. This ioctl
will fail only when there are no video outputs, returning the
&EINVAL;.</para>
<para>To select a video output applications store the number of the
desired output in an integer and call the
<constant>VIDIOC_S_OUTPUT</constant> ioctl with a pointer to this integer.
Side effects are possible. For example outputs may support different
video standards, so the driver may implicitly switch the current
standard. It is good practice to select an output before querying or
negotiating any other parameters.</para>
<para>Information about video outputs is available using the
&VIDIOC-ENUMOUTPUT; ioctl.</para>
</refsect1>
<refsect1>
&return-value;
<variablelist>
<varlistentry>
<term><errorcode>EINVAL</errorcode></term>
<listitem>
<para>The number of the video output is out of bounds, or
there are no video outputs at all and this ioctl is not
supported.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>EBUSY</errorcode></term>
<listitem>
<para>I/O is in progress, the output cannot be
switched.</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
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