<refentry id="media-ioc-enum-entities"> <refmeta> <refentrytitle>ioctl MEDIA_IOC_ENUM_ENTITIES</refentrytitle> &manvol; </refmeta> <refnamediv> <refname>MEDIA_IOC_ENUM_ENTITIES</refname> <refpurpose>Enumerate entities and their properties</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 media_entity_desc *<parameter>argp</parameter></paramdef> </funcprototype> </funcsynopsis> </refsynopsisdiv> <refsect1> <title>Arguments</title> <variablelist> <varlistentry> <term><parameter>fd</parameter></term> <listitem> <para>File descriptor returned by <link linkend='media-func-open'><function>open()</function></link>.</para> </listitem> </varlistentry> <varlistentry> <term><parameter>request</parameter></term> <listitem> <para>MEDIA_IOC_ENUM_ENTITIES</para> </listitem> </varlistentry> <varlistentry> <term><parameter>argp</parameter></term> <listitem> <para></para> </listitem> </varlistentry> </variablelist> </refsect1> <refsect1> <title>Description</title> <para>To query the attributes of an entity, applications set the id field of a &media-entity-desc; structure and call the MEDIA_IOC_ENUM_ENTITIES ioctl with a pointer to this structure. The driver fills the rest of the structure or returns an &EINVAL; when the id is invalid.</para> <para>Entities can be enumerated by or'ing the id with the <constant>MEDIA_ENT_ID_FLAG_NEXT</constant> flag. The driver will return information about the entity with the smallest id strictly larger than the requested one ('next entity'), or the &EINVAL; if there is none.</para> <para>Entity IDs can be non-contiguous. Applications must <emphasis>not</emphasis> try to enumerate entities by calling MEDIA_IOC_ENUM_ENTITIES with increasing id's until they get an error.</para> <para>Two or more entities that share a common non-zero <structfield>group_id</structfield> value are considered as logically grouped. Groups are used to report <itemizedlist> <listitem><para>ALSA, VBI and video nodes that carry the same media stream</para></listitem> <listitem><para>lens and flash controllers associated with a sensor</para></listitem> </itemizedlist> </para> <table pgwide="1" frame="none" id="media-entity-desc"> <title>struct <structname>media_entity_desc</structname></title> <tgroup cols="5"> <colspec colname="c1" /> <colspec colname="c2" /> <colspec colname="c3" /> <colspec colname="c4" /> <colspec colname="c5" /> <tbody valign="top"> <row> <entry>__u32</entry> <entry><structfield>id</structfield></entry> <entry></entry> <entry></entry> <entry>Entity id, set by the application. When the id is or'ed with <constant>MEDIA_ENT_ID_FLAG_NEXT</constant>, the driver clears the flag and returns the first entity with a larger id.</entry> </row> <row> <entry>char</entry> <entry><structfield>name</structfield>[32]</entry> <entry></entry> <entry></entry> <entry>Entity name as an UTF-8 NULL-terminated string.</entry> </row> <row> <entry>__u32</entry> <entry><structfield>type</structfield></entry> <entry></entry> <entry></entry> <entry>Entity type, see <xref linkend="media-entity-type" /> for details.</entry> </row> <row> <entry>__u32</entry> <entry><structfield>revision</structfield></entry> <entry></entry> <entry></entry> <entry>Entity revision in a driver/hardware specific format.</entry> </row> <row> <entry>__u32</entry> <entry><structfield>flags</structfield></entry> <entry></entry> <entry></entry> <entry>Entity flags, see <xref linkend="media-entity-flag" /> for details.</entry> </row> <row> <entry>__u32</entry> <entry><structfield>group_id</structfield></entry> <entry></entry> <entry></entry> <entry>Entity group ID</entry> </row> <row> <entry>__u16</entry> <entry><structfield>pads</structfield></entry> <entry></entry> <entry></entry> <entry>Number of pads</entry> </row> <row> <entry>__u16</entry> <entry><structfield>links</structfield></entry> <entry></entry> <entry></entry> <entry>Total number of outbound links. Inbound links are not counted in this field.</entry> </row> <row> <entry>union</entry> </row> <row> <entry></entry> <entry>struct</entry> <entry><structfield>v4l</structfield></entry> <entry></entry> <entry>Valid for V4L sub-devices and nodes only.</entry> </row> <row> <entry></entry> <entry></entry> <entry>__u32</entry> <entry><structfield>major</structfield></entry> <entry>V4L device node major number. For V4L sub-devices with no device node, set by the driver to 0.</entry> </row> <row> <entry></entry> <entry></entry> <entry>__u32</entry> <entry><structfield>minor</structfield></entry> <entry>V4L device node minor number. For V4L sub-devices with no device node, set by the driver to 0.</entry> </row> <row> <entry></entry> <entry>struct</entry> <entry><structfield>fb</structfield></entry> <entry></entry> <entry>Valid for frame buffer nodes only.</entry> </row> <row> <entry></entry> <entry></entry> <entry>__u32</entry> <entry><structfield>major</structfield></entry> <entry>Frame buffer device node major number.</entry> </row> <row> <entry></entry> <entry></entry> <entry>__u32</entry> <entry><structfield>minor</structfield></entry> <entry>Frame buffer device node minor number.</entry> </row> <row> <entry></entry> <entry>struct</entry> <entry><structfield>alsa</structfield></entry> <entry></entry> <entry>Valid for ALSA devices only.</entry> </row> <row> <entry></entry> <entry></entry> <entry>__u32</entry> <entry><structfield>card</structfield></entry> <entry>ALSA card number</entry> </row> <row> <entry></entry> <entry></entry> <entry>__u32</entry> <entry><structfield>device</structfield></entry> <entry>ALSA device number</entry> </row> <row> <entry></entry> <entry></entry> <entry>__u32</entry> <entry><structfield>subdevice</structfield></entry> <entry>ALSA sub-device number</entry> </row> <row> <entry></entry> <entry>int</entry> <entry><structfield>dvb</structfield></entry> <entry></entry> <entry>DVB card number</entry> </row> <row> <entry></entry> <entry>__u8</entry> <entry><structfield>raw</structfield>[180]</entry> <entry></entry> <entry></entry> </row> </tbody> </tgroup> </table> <table frame="none" pgwide="1" id="media-entity-type"> <title>Media entity types</title> <tgroup cols="2"> <colspec colname="c1"/> <colspec colname="c2"/> <tbody valign="top"> <row> <entry><constant>MEDIA_ENT_T_DEVNODE</constant></entry> <entry>Unknown device node</entry> </row> <row> <entry><constant>MEDIA_ENT_T_DEVNODE_V4L</constant></entry> <entry>V4L video, radio or vbi device node</entry> </row> <row> <entry><constant>MEDIA_ENT_T_DEVNODE_FB</constant></entry> <entry>Frame buffer device node</entry> </row> <row> <entry><constant>MEDIA_ENT_T_DEVNODE_ALSA</constant></entry> <entry>ALSA card</entry> </row> <row> <entry><constant>MEDIA_ENT_T_DEVNODE_DVB</constant></entry> <entry>DVB card</entry> </row> <row> <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV</constant></entry> <entry>Unknown V4L sub-device</entry> </row> <row> <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_SENSOR</constant></entry> <entry>Video sensor</entry> </row> <row> <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_FLASH</constant></entry> <entry>Flash controller</entry> </row> <row> <entry><constant>MEDIA_ENT_T_V4L2_SUBDEV_LENS</constant></entry> <entry>Lens controller</entry> </row> </tbody> </tgroup> </table> <table frame="none" pgwide="1" id="media-entity-flag"> <title>Media entity flags</title> <tgroup cols="2"> <colspec colname="c1"/> <colspec colname="c2"/> <tbody valign="top"> <row> <entry><constant>MEDIA_ENT_FL_DEFAULT</constant></entry> <entry>Default entity for its type. Used to discover the default audio, VBI and video devices, the default camera sensor, ...</entry> </row> </tbody> </tgroup> </table> </refsect1> <refsect1> &return-value; <variablelist> <varlistentry> <term><errorcode>EINVAL</errorcode></term> <listitem> <para>The &media-entity-desc; <structfield>id</structfield> references a non-existing entity.</para> </listitem> </varlistentry> </variablelist> </refsect1> </refentry>