Based on kernel version 4.7.2. Page generated on 2016-08-22 22:45 EST.
1 <refentry id="media-ioc-enum-entities"> 2 <refmeta> 3 <refentrytitle>ioctl MEDIA_IOC_ENUM_ENTITIES</refentrytitle> 4 &manvol; 5 </refmeta> 6 7 <refnamediv> 8 <refname>MEDIA_IOC_ENUM_ENTITIES</refname> 9 <refpurpose>Enumerate entities and their properties</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 media_entity_desc *<parameter>argp</parameter></paramdef> 19 </funcprototype> 20 </funcsynopsis> 21 </refsynopsisdiv> 22 23 <refsect1> 24 <title>Arguments</title> 25 26 <variablelist> 27 <varlistentry> 28 <term><parameter>fd</parameter></term> 29 <listitem> 30 <para>File descriptor returned by 31 <link linkend='media-func-open'><function>open()</function></link>.</para> 32 </listitem> 33 </varlistentry> 34 <varlistentry> 35 <term><parameter>request</parameter></term> 36 <listitem> 37 <para>MEDIA_IOC_ENUM_ENTITIES</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 <para>To query the attributes of an entity, applications set the id field 52 of a &media-entity-desc; structure and call the MEDIA_IOC_ENUM_ENTITIES 53 ioctl with a pointer to this structure. The driver fills the rest of the 54 structure or returns an &EINVAL; when the id is invalid.</para> 55 <para>Entities can be enumerated by or'ing the id with the 56 <constant>MEDIA_ENT_ID_FLAG_NEXT</constant> flag. The driver will return 57 information about the entity with the smallest id strictly larger than the 58 requested one ('next entity'), or the &EINVAL; if there is none.</para> 59 <para>Entity IDs can be non-contiguous. Applications must 60 <emphasis>not</emphasis> try to enumerate entities by calling 61 MEDIA_IOC_ENUM_ENTITIES with increasing id's until they get an error.</para> 62 63 <table pgwide="1" frame="none" id="media-entity-desc"> 64 <title>struct <structname>media_entity_desc</structname></title> 65 <tgroup cols="5"> 66 <colspec colname="c1" /> 67 <colspec colname="c2" /> 68 <colspec colname="c3" /> 69 <colspec colname="c4" /> 70 <colspec colname="c5" /> 71 <tbody valign="top"> 72 <row> 73 <entry>__u32</entry> 74 <entry><structfield>id</structfield></entry> 75 <entry></entry> 76 <entry></entry> 77 <entry>Entity id, set by the application. When the id is or'ed with 78 <constant>MEDIA_ENT_ID_FLAG_NEXT</constant>, the driver clears the 79 flag and returns the first entity with a larger id.</entry> 80 </row> 81 <row> 82 <entry>char</entry> 83 <entry><structfield>name</structfield>[32]</entry> 84 <entry></entry> 85 <entry></entry> 86 <entry>Entity name as an UTF-8 NULL-terminated string.</entry> 87 </row> 88 <row> 89 <entry>__u32</entry> 90 <entry><structfield>type</structfield></entry> 91 <entry></entry> 92 <entry></entry> 93 <entry>Entity type, see <xref linkend="media-entity-type" /> for details.</entry> 94 </row> 95 <row> 96 <entry>__u32</entry> 97 <entry><structfield>revision</structfield></entry> 98 <entry></entry> 99 <entry></entry> 100 <entry>Entity revision. Always zero (obsolete)</entry> 101 </row> 102 <row> 103 <entry>__u32</entry> 104 <entry><structfield>flags</structfield></entry> 105 <entry></entry> 106 <entry></entry> 107 <entry>Entity flags, see <xref linkend="media-entity-flag" /> for details.</entry> 108 </row> 109 <row> 110 <entry>__u32</entry> 111 <entry><structfield>group_id</structfield></entry> 112 <entry></entry> 113 <entry></entry> 114 <entry>Entity group ID. Always zero (obsolete)</entry> 115 </row> 116 <row> 117 <entry>__u16</entry> 118 <entry><structfield>pads</structfield></entry> 119 <entry></entry> 120 <entry></entry> 121 <entry>Number of pads</entry> 122 </row> 123 <row> 124 <entry>__u16</entry> 125 <entry><structfield>links</structfield></entry> 126 <entry></entry> 127 <entry></entry> 128 <entry>Total number of outbound links. Inbound links are not counted 129 in this field.</entry> 130 </row> 131 <row> 132 <entry>union</entry> 133 </row> 134 <row> 135 <entry></entry> 136 <entry>struct</entry> 137 <entry><structfield>dev</structfield></entry> 138 <entry></entry> 139 <entry>Valid for (sub-)devices that create a single device node.</entry> 140 </row> 141 <row> 142 <entry></entry> 143 <entry></entry> 144 <entry>__u32</entry> 145 <entry><structfield>major</structfield></entry> 146 <entry>Device node major number.</entry> 147 </row> 148 <row> 149 <entry></entry> 150 <entry></entry> 151 <entry>__u32</entry> 152 <entry><structfield>minor</structfield></entry> 153 <entry>Device node minor number.</entry> 154 </row> 155 <row> 156 <entry></entry> 157 <entry>__u8</entry> 158 <entry><structfield>raw</structfield>[184]</entry> 159 <entry></entry> 160 <entry></entry> 161 </row> 162 </tbody> 163 </tgroup> 164 </table> 165 </refsect1> 166 167 <refsect1> 168 &return-value; 169 170 <variablelist> 171 <varlistentry> 172 <term><errorcode>EINVAL</errorcode></term> 173 <listitem> 174 <para>The &media-entity-desc; <structfield>id</structfield> references 175 a non-existing entity.</para> 176 </listitem> 177 </varlistentry> 178 </variablelist> 179 </refsect1> 180 </refentry>
