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Diffstat (limited to 'Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml')
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diff --git a/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml deleted file mode 100644 index 781089cba453..000000000000 --- a/Documentation/DocBook/media/v4l/vidioc-subdev-g-fmt.xml +++ /dev/null @@ -1,177 +0,0 @@ -<refentry id="vidioc-subdev-g-fmt"> - <refmeta> - <refentrytitle>ioctl VIDIOC_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT</refentrytitle> - &manvol; - </refmeta> - - <refnamediv> - <refname>VIDIOC_SUBDEV_G_FMT</refname> - <refname>VIDIOC_SUBDEV_S_FMT</refname> - <refpurpose>Get or set the data format on a subdev pad</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_subdev_format *<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_SUBDEV_G_FMT, VIDIOC_SUBDEV_S_FMT</para> - </listitem> - </varlistentry> - <varlistentry> - <term><parameter>argp</parameter></term> - <listitem> - <para></para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> - - <refsect1> - <title>Description</title> - - <para>These ioctls are used to negotiate the frame format at specific - subdev pads in the image pipeline.</para> - - <para>To retrieve the current format applications set the - <structfield>pad</structfield> field of a &v4l2-subdev-format; to the - desired pad number as reported by the media API and the - <structfield>which</structfield> field to - <constant>V4L2_SUBDEV_FORMAT_ACTIVE</constant>. When they call the - <constant>VIDIOC_SUBDEV_G_FMT</constant> ioctl with a pointer to this - structure the driver fills the members of the <structfield>format</structfield> - field.</para> - - <para>To change the current format applications set both the - <structfield>pad</structfield> and <structfield>which</structfield> fields - and all members of the <structfield>format</structfield> field. When they - call the <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl with a pointer to this - structure the driver verifies the requested format, adjusts it based on the - hardware capabilities and configures the device. Upon return the - &v4l2-subdev-format; contains the current format as would be returned by a - <constant>VIDIOC_SUBDEV_G_FMT</constant> call.</para> - - <para>Applications can query the device capabilities by setting the - <structfield>which</structfield> to - <constant>V4L2_SUBDEV_FORMAT_TRY</constant>. When set, 'try' formats are not - applied to the device by the driver, but are changed exactly as active - formats and stored in the sub-device file handle. Two applications querying - the same sub-device would thus not interact with each other.</para> - - <para>For instance, to try a format at the output pad of a sub-device, - applications would first set the try format at the sub-device input with the - <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl. They would then either - retrieve the default format at the output pad with the - <constant>VIDIOC_SUBDEV_G_FMT</constant> ioctl, or set the desired output - pad format with the <constant>VIDIOC_SUBDEV_S_FMT</constant> ioctl and check - the returned value.</para> - - <para>Try formats do not depend on active formats, but can depend on the - current links configuration or sub-device controls value. For instance, a - low-pass noise filter might crop pixels at the frame boundaries, modifying - its output frame size.</para> - - <para>Drivers must not return an error solely because the requested format - doesn't match the device capabilities. They must instead modify the format - to match what the hardware can provide. The modified format should be as - close as possible to the original request.</para> - - <table pgwide="1" frame="none" id="v4l2-subdev-format"> - <title>struct <structname>v4l2_subdev_format</structname></title> - <tgroup cols="3"> - &cs-str; - <tbody valign="top"> - <row> - <entry>__u32</entry> - <entry><structfield>pad</structfield></entry> - <entry>Pad number as reported by the media controller API.</entry> - </row> - <row> - <entry>__u32</entry> - <entry><structfield>which</structfield></entry> - <entry>Format to modified, from &v4l2-subdev-format-whence;.</entry> - </row> - <row> - <entry>&v4l2-mbus-framefmt;</entry> - <entry><structfield>format</structfield></entry> - <entry>Definition of an image format, see <xref - linkend="v4l2-mbus-framefmt" /> for details.</entry> - </row> - <row> - <entry>__u32</entry> - <entry><structfield>reserved</structfield>[8]</entry> - <entry>Reserved for future extensions. Applications and drivers must - set the array to zero.</entry> - </row> - </tbody> - </tgroup> - </table> - - <table pgwide="1" frame="none" id="v4l2-subdev-format-whence"> - <title>enum <structname>v4l2_subdev_format_whence</structname></title> - <tgroup cols="3"> - &cs-def; - <tbody valign="top"> - <row> - <entry>V4L2_SUBDEV_FORMAT_TRY</entry> - <entry>0</entry> - <entry>Try formats, used for querying device capabilities.</entry> - </row> - <row> - <entry>V4L2_SUBDEV_FORMAT_ACTIVE</entry> - <entry>1</entry> - <entry>Active formats, applied to the hardware.</entry> - </row> - </tbody> - </tgroup> - </table> - </refsect1> - - <refsect1> - &return-value; - - <variablelist> - <varlistentry> - <term><errorcode>EBUSY</errorcode></term> - <listitem> - <para>The format can't be changed because the pad is currently busy. - This can be caused, for instance, by an active video stream on the - pad. The ioctl must not be retried without performing another action - to fix the problem first. Only returned by - <constant>VIDIOC_SUBDEV_S_FMT</constant></para> - </listitem> - </varlistentry> - <varlistentry> - <term><errorcode>EINVAL</errorcode></term> - <listitem> - <para>The &v4l2-subdev-format; <structfield>pad</structfield> - references a non-existing pad, or the <structfield>which</structfield> - field references a non-existing format.</para> - </listitem> - </varlistentry> - </variablelist> - </refsect1> - <refsect1> - &return-value; - </refsect1> -</refentry> |