diff options
Diffstat (limited to 'Documentation/DocBook/v4l/vidioc-subdev-enum-frame-size.xml')
| -rw-r--r-- | Documentation/DocBook/v4l/vidioc-subdev-enum-frame-size.xml | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/Documentation/DocBook/v4l/vidioc-subdev-enum-frame-size.xml b/Documentation/DocBook/v4l/vidioc-subdev-enum-frame-size.xml new file mode 100644 index 00000000..79ce42b7 --- /dev/null +++ b/Documentation/DocBook/v4l/vidioc-subdev-enum-frame-size.xml @@ -0,0 +1,154 @@ +<refentry id="vidioc-subdev-enum-frame-size"> + <refmeta> + <refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refentrytitle> + &manvol; + </refmeta> + + <refnamediv> + <refname>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refname> + <refpurpose>Enumerate media bus frame sizes</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_frame_size_enum * + <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_ENUM_FRAME_SIZE</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>This ioctl allows applications to enumerate all frame sizes + supported by a sub-device on the given pad for the given media bus format. + Supported formats can be retrieved with the &VIDIOC-SUBDEV-ENUM-MBUS-CODE; + ioctl.</para> + + <para>To enumerate frame sizes applications initialize the + <structfield>pad</structfield>, <structfield>code</structfield> and + <structfield>index</structfield> fields of the + &v4l2-subdev-mbus-code-enum; and call the + <constant>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</constant> ioctl with a pointer to + the structure. Drivers fill the minimum and maximum frame sizes or return + an &EINVAL; if one of the input parameters is invalid.</para> + + <para>Sub-devices that only support discrete frame sizes (such as most + sensors) will return one or more frame sizes with identical minimum and + maximum values.</para> + + <para>Not all possible sizes in given [minimum, maximum] ranges need to be + supported. For instance, a scaler that uses a fixed-point scaling ratio + might not be able to produce every frame size between the minimum and + maximum values. Applications must use the &VIDIOC-SUBDEV-S-FMT; ioctl to + try the sub-device for an exact supported frame size.</para> + + <para>Available frame sizes may depend on the current 'try' formats at other + pads of the sub-device, as well as on the current active links and the + current values of V4L2 controls. See &VIDIOC-SUBDEV-G-FMT; for more + information about try formats.</para> + + <table pgwide="1" frame="none" id="v4l2-subdev-frame-size-enum"> + <title>struct <structname>v4l2_subdev_frame_size_enum</structname></title> + <tgroup cols="3"> + &cs-str; + <tbody valign="top"> + <row> + <entry>__u32</entry> + <entry><structfield>index</structfield></entry> + <entry>Number of the format in the enumeration, set by the + application.</entry> + </row> + <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>code</structfield></entry> + <entry>The media bus format code, as defined in + <xref linkend="v4l2-mbus-format" />.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>min_width</structfield></entry> + <entry>Minimum frame width, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>max_width</structfield></entry> + <entry>Maximum frame width, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>min_height</structfield></entry> + <entry>Minimum frame height, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>max_height</structfield></entry> + <entry>Maximum frame height, in pixels.</entry> + </row> + <row> + <entry>__u32</entry> + <entry><structfield>reserved</structfield>[9]</entry> + <entry>Reserved for future extensions. Applications and drivers must + set the array to zero.</entry> + </row> + </tbody> + </tgroup> + </table> + </refsect1> + + <refsect1> + &return-value; + + <variablelist> + <varlistentry> + <term><errorcode>EINVAL</errorcode></term> + <listitem> + <para>The &v4l2-subdev-frame-size-enum; <structfield>pad</structfield> + references a non-existing pad, the <structfield>code</structfield> is + invalid for the given pad or the <structfield>index</structfield> + field is out of bounds.</para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> +</refentry> |