Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 EST.
1 <refentry id="vidioc-subdev-enum-frame-size"> 2 <refmeta> 3 <refentrytitle>ioctl VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</refname> 9 <refpurpose>Enumerate media bus frame sizes</refpurpose> 10 </refnamediv> 11 12 <refsynopsisdiv> 13 <funcsynopsis> 14 <funcprototype> 15 <funcdef>int <function>ioctl</function></funcdef> 16 <paramdef>int <parameter>fd</parameter></paramdef> 17 <paramdef>int <parameter>request</parameter></paramdef> 18 <paramdef>struct v4l2_subdev_frame_size_enum * 19 <parameter>argp</parameter></paramdef> 20 </funcprototype> 21 </funcsynopsis> 22 </refsynopsisdiv> 23 24 <refsect1> 25 <title>Arguments</title> 26 27 <variablelist> 28 <varlistentry> 29 <term><parameter>fd</parameter></term> 30 <listitem> 31 <para>&fd;</para> 32 </listitem> 33 </varlistentry> 34 <varlistentry> 35 <term><parameter>request</parameter></term> 36 <listitem> 37 <para>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</para> 38 </listitem> 39 </varlistentry> 40 <varlistentry> 41 <term><parameter>argp</parameter></term> 42 <listitem> 43 <para></para> 44 </listitem> 45 </varlistentry> 46 </variablelist> 47 </refsect1> 48 49 <refsect1> 50 <title>Description</title> 51 52 <para>This ioctl allows applications to enumerate all frame sizes 53 supported by a sub-device on the given pad for the given media bus format. 54 Supported formats can be retrieved with the &VIDIOC-SUBDEV-ENUM-MBUS-CODE; 55 ioctl.</para> 56 57 <para>To enumerate frame sizes applications initialize the 58 <structfield>pad</structfield>, <structfield>which</structfield> , 59 <structfield>code</structfield> and <structfield>index</structfield> 60 fields of the &v4l2-subdev-mbus-code-enum; and call the 61 <constant>VIDIOC_SUBDEV_ENUM_FRAME_SIZE</constant> ioctl with a pointer to 62 the structure. Drivers fill the minimum and maximum frame sizes or return 63 an &EINVAL; if one of the input parameters is invalid.</para> 64 65 <para>Sub-devices that only support discrete frame sizes (such as most 66 sensors) will return one or more frame sizes with identical minimum and 67 maximum values.</para> 68 69 <para>Not all possible sizes in given [minimum, maximum] ranges need to be 70 supported. For instance, a scaler that uses a fixed-point scaling ratio 71 might not be able to produce every frame size between the minimum and 72 maximum values. Applications must use the &VIDIOC-SUBDEV-S-FMT; ioctl to 73 try the sub-device for an exact supported frame size.</para> 74 75 <para>Available frame sizes may depend on the current 'try' formats at other 76 pads of the sub-device, as well as on the current active links and the 77 current values of V4L2 controls. See &VIDIOC-SUBDEV-G-FMT; for more 78 information about try formats.</para> 79 80 <table pgwide="1" frame="none" id="v4l2-subdev-frame-size-enum"> 81 <title>struct <structname>v4l2_subdev_frame_size_enum</structname></title> 82 <tgroup cols="3"> 83 &cs-str; 84 <tbody valign="top"> 85 <row> 86 <entry>__u32</entry> 87 <entry><structfield>index</structfield></entry> 88 <entry>Number of the format in the enumeration, set by the 89 application.</entry> 90 </row> 91 <row> 92 <entry>__u32</entry> 93 <entry><structfield>pad</structfield></entry> 94 <entry>Pad number as reported by the media controller API.</entry> 95 </row> 96 <row> 97 <entry>__u32</entry> 98 <entry><structfield>code</structfield></entry> 99 <entry>The media bus format code, as defined in 100 <xref linkend="v4l2-mbus-format" />.</entry> 101 </row> 102 <row> 103 <entry>__u32</entry> 104 <entry><structfield>min_width</structfield></entry> 105 <entry>Minimum frame width, in pixels.</entry> 106 </row> 107 <row> 108 <entry>__u32</entry> 109 <entry><structfield>max_width</structfield></entry> 110 <entry>Maximum frame width, in pixels.</entry> 111 </row> 112 <row> 113 <entry>__u32</entry> 114 <entry><structfield>min_height</structfield></entry> 115 <entry>Minimum frame height, in pixels.</entry> 116 </row> 117 <row> 118 <entry>__u32</entry> 119 <entry><structfield>max_height</structfield></entry> 120 <entry>Maximum frame height, in pixels.</entry> 121 </row> 122 <row> 123 <entry>__u32</entry> 124 <entry><structfield>which</structfield></entry> 125 <entry>Frame sizes to be enumerated, from &v4l2-subdev-format-whence;.</entry> 126 </row> 127 <row> 128 <entry>__u32</entry> 129 <entry><structfield>reserved</structfield>[8]</entry> 130 <entry>Reserved for future extensions. Applications and drivers must 131 set the array to zero.</entry> 132 </row> 133 </tbody> 134 </tgroup> 135 </table> 136 </refsect1> 137 138 <refsect1> 139 &return-value; 140 141 <variablelist> 142 <varlistentry> 143 <term><errorcode>EINVAL</errorcode></term> 144 <listitem> 145 <para>The &v4l2-subdev-frame-size-enum; <structfield>pad</structfield> 146 references a non-existing pad, the <structfield>code</structfield> is 147 invalid for the given pad or the <structfield>index</structfield> 148 field is out of bounds.</para> 149 </listitem> 150 </varlistentry> 151 </variablelist> 152 </refsect1> 153 </refentry>
