1b88db2f2b
Field 'rect' is really named 'r'. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
165 lines
5 KiB
XML
165 lines
5 KiB
XML
<refentry id="vidioc-subdev-g-selection">
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<refmeta>
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<refentrytitle>ioctl VIDIOC_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION</refentrytitle>
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&manvol;
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</refmeta>
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<refnamediv>
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<refname>VIDIOC_SUBDEV_G_SELECTION</refname>
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<refname>VIDIOC_SUBDEV_S_SELECTION</refname>
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<refpurpose>Get or set selection rectangles on a subdev pad</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>struct v4l2_subdev_selection *<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_SUBDEV_G_SELECTION, VIDIOC_SUBDEV_S_SELECTION</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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<note>
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<title>Experimental</title>
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<para>This is an <link linkend="experimental">experimental</link>
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interface and may change in the future.</para>
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</note>
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<para>The selections are used to configure various image
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processing functionality performed by the subdevs which affect the
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image size. This currently includes cropping, scaling and
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composition.</para>
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<para>The selection API replaces <link
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linkend="vidioc-subdev-g-crop">the old subdev crop API</link>. All
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the function of the crop API, and more, are supported by the
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selections API.</para>
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<para>See <xref linkend="subdev"></xref> for
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more information on how each selection target affects the image
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processing pipeline inside the subdevice.</para>
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<refsect2>
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<title>Types of selection targets</title>
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<para>There are two types of selection targets: actual and bounds. The
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actual targets are the targets which configure the hardware. The BOUNDS
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target will return a rectangle that contain all possible actual
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rectangles.</para>
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</refsect2>
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<refsect2>
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<title>Discovering supported features</title>
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<para>To discover which targets are supported, the user can
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perform <constant>VIDIOC_SUBDEV_G_SELECTION</constant> on them.
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Any unsupported target will return
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<constant>EINVAL</constant>.</para>
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<para>Selection targets and flags are documented in <xref
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linkend="v4l2-selections-common"/>.</para>
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<table pgwide="1" frame="none" id="v4l2-subdev-selection">
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<title>struct <structname>v4l2_subdev_selection</structname></title>
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<tgroup cols="3">
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&cs-str;
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<tbody valign="top">
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<row>
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<entry>__u32</entry>
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<entry><structfield>which</structfield></entry>
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<entry>Active or try selection, from
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&v4l2-subdev-format-whence;.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>pad</structfield></entry>
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<entry>Pad number as reported by the media framework.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>target</structfield></entry>
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<entry>Target selection rectangle. See
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<xref linkend="v4l2-selections-common" />.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>flags</structfield></entry>
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<entry>Flags. See
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<xref linkend="v4l2-selection-flags" />.</entry>
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</row>
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<row>
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<entry>&v4l2-rect;</entry>
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<entry><structfield>r</structfield></entry>
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<entry>Selection rectangle, in pixels.</entry>
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</row>
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<row>
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<entry>__u32</entry>
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<entry><structfield>reserved</structfield>[8]</entry>
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<entry>Reserved for future extensions. Applications and drivers must
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set the array to zero.</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</refsect2>
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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>EBUSY</errorcode></term>
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<listitem>
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<para>The selection rectangle can't be changed because the
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pad is currently busy. This can be caused, for instance, by
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an active video stream on the pad. The ioctl must not be
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retried without performing another action to fix the problem
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first. Only returned by
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<constant>VIDIOC_SUBDEV_S_SELECTION</constant></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><errorcode>EINVAL</errorcode></term>
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<listitem>
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<para>The &v4l2-subdev-selection;
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<structfield>pad</structfield> references a non-existing
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pad, the <structfield>which</structfield> field references a
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non-existing format, or the selection target is not
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supported on the given subdev pad.</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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