f1158af2b2
Make explicit what should happen when the input signal is missing, unreliable or does not map to a supported preset. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
88 lines
2.2 KiB
XML
88 lines
2.2 KiB
XML
<refentry id="vidioc-query-dv-preset">
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<refmeta>
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<refentrytitle>ioctl VIDIOC_QUERY_DV_PRESET</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>VIDIOC_QUERY_DV_PRESET</refname>
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<refpurpose>Sense the DV preset received by the current
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input</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcprototype>
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<funcdef>int <function>ioctl</function></funcdef>
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<paramdef>int <parameter>fd</parameter></paramdef>
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<paramdef>int <parameter>request</parameter></paramdef>
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<paramdef>&v4l2-dv-preset; *<parameter>argp</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Arguments</title>
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<variablelist>
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<varlistentry>
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<term><parameter>fd</parameter></term>
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<listitem>
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<para>&fd;</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>request</parameter></term>
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<listitem>
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<para>VIDIOC_QUERY_DV_PRESET</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>argp</parameter></term>
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<listitem>
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<para></para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Description</title>
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<para>The hardware may be able to detect the current DV preset
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automatically, similar to sensing the video standard. To do so, applications
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call <constant> VIDIOC_QUERY_DV_PRESET</constant> with a pointer to a
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&v4l2-dv-preset; type. Once the hardware detects a preset, that preset is
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returned in the preset field of &v4l2-dv-preset;. If the preset could not be
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detected because there was no signal, or the signal was unreliable, or the
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signal did not map to a supported preset, then the value V4L2_DV_INVALID is
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returned.</para>
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</refsect1>
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<refsect1>
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&return-value;
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<variablelist>
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<varlistentry>
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<term><errorcode>EINVAL</errorcode></term>
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<listitem>
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<para>This ioctl is not supported.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>EBUSY</errorcode></term>
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<listitem>
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<para>The device is busy and therefore can not sense the preset</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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</refentry>
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<!--
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Local Variables:
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mode: sgml
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sgml-parent-document: "v4l2.sgml"
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indent-tabs-mode: nil
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End:
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-->
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