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Diffstat (limited to 'kernel/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml')
-rw-r--r-- | kernel/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/kernel/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml b/kernel/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml new file mode 100644 index 000000000..e185f149e --- /dev/null +++ b/kernel/Documentation/DocBook/media/v4l/vidioc-query-dv-timings.xml @@ -0,0 +1,110 @@ +<refentry id="vidioc-query-dv-timings"> + <refmeta> + <refentrytitle>ioctl VIDIOC_QUERY_DV_TIMINGS</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_QUERY_DV_TIMINGS</refname> + <refpurpose>Sense the DV preset 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>struct v4l2_dv_timings *<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_QUERY_DV_TIMINGS</para> + </listitem> + </varlistentry> + <varlistentry> + <term><parameter>argp</parameter></term> + <listitem> + <para></para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1> + <title>Description</title> + + <note> + <title>Experimental</title> + <para>This is an <link linkend="experimental"> experimental </link> + interface and may change in the future.</para> + </note> + + <para>The hardware may be able to detect the current DV timings +automatically, similar to sensing the video standard. To do so, applications +call <constant>VIDIOC_QUERY_DV_TIMINGS</constant> with a pointer to a +&v4l2-dv-timings;. Once the hardware detects the timings, it will fill in the +timings structure. + +If the timings could not be detected because there was no signal, then +<errorcode>ENOLINK</errorcode> is returned. If a signal was detected, but +it was unstable and the receiver could not lock to the signal, then +<errorcode>ENOLCK</errorcode> is returned. If the receiver could lock to the signal, +but the format is unsupported (e.g. because the pixelclock is out of range +of the hardware capabilities), then the driver fills in whatever timings it +could find and returns <errorcode>ERANGE</errorcode>. In that case the application +can call &VIDIOC-DV-TIMINGS-CAP; to compare the found timings with the hardware's +capabilities in order to give more precise feedback to the user. +</para> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>ENODATA</errorcode></term> + <listitem> + <para>Digital video timings are not supported for this input or output.</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOLINK</errorcode></term> + <listitem> + <para>No timings could be detected because no signal was found. +</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ENOLCK</errorcode></term> + <listitem> + <para>The signal was unstable and the hardware could not lock on to it. +</para> + </listitem> + </varlistentry> + <varlistentry> + <term><errorcode>ERANGE</errorcode></term> + <listitem> + <para>Timings were found, but they are out of range of the hardware +capabilities. +</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> |