linux/Documentation/DocBook/v4l/vidioc-querystd.xml
Muralidharan Karicheri 422eaac5d5 V4L/DVB (13619): v4l2-spec: Adds EBUSY error code for S_STD and QUERYSTD ioctls
During review of Video Timing API documentation, Hans Verkuil had a comment
on adding EBUSY error code for VIDIOC_S_STD and VIDIOC_QUERYSTD ioctls. This
patch updates the document for this.

Signed-off-by: Muralidharan Karicheri <m-karicheri2@ti.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2009-12-16 00:18:47 -02:00

90 lines
2.2 KiB
XML

<refentry id="vidioc-querystd">
<refmeta>
<refentrytitle>ioctl VIDIOC_QUERYSTD</refentrytitle>
&manvol;
</refmeta>
<refnamediv>
<refname>VIDIOC_QUERYSTD</refname>
<refpurpose>Sense the video standard received by the current
input</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcprototype>
<funcdef>int <function>ioctl</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>request</parameter></paramdef>
<paramdef>v4l2_std_id *<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_QUERYSTD</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>argp</parameter></term>
<listitem>
<para></para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Description</title>
<para>The hardware may be able to detect the current video
standard automatically. To do so, applications call <constant>
VIDIOC_QUERYSTD</constant> with a pointer to a &v4l2-std-id; type. The
driver stores here a set of candidates, this can be a single flag or a
set of supported standards if for example the hardware can only
distinguish between 50 and 60 Hz systems. When detection is not
possible or fails, the set must contain all standards supported by the
current video input or output.</para>
</refsect1>
<refsect1>
&return-value;
<variablelist>
<varlistentry>
<term><errorcode>EINVAL</errorcode></term>
<listitem>
<para>This ioctl is not supported.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><errorcode>EBUSY</errorcode></term>
<listitem>
<para>The device is busy and therefore can not detect the standard</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
</refentry>
<!--
Local Variables:
mode: sgml
sgml-parent-document: "v4l2.sgml"
indent-tabs-mode: nil
End:
-->