.. Permission is granted to copy, distribute and/or modify this .. document under the terms of the GNU Free Documentation License, .. Version 1.1 or any later version published by the Free Software .. Foundation, with no Invariant Sections, no Front-Cover Texts .. and no Back-Cover Texts. A copy of the license is included at .. Documentation/userspace-api/media/fdl-appendix.rst. .. .. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections .. _media_ioc_enum_entities: ***************************** ioctl MEDIA_IOC_ENUM_ENTITIES ***************************** Name ==== MEDIA_IOC_ENUM_ENTITIES - Enumerate entities and their properties Synopsis ======== .. c:function:: int ioctl( int fd, MEDIA_IOC_ENUM_ENTITIES, struct media_entity_desc *argp ) :name: MEDIA_IOC_ENUM_ENTITIES Arguments ========= ``fd`` File descriptor returned by :ref:`open() `. ``argp`` Pointer to struct :c:type:`media_entity_desc`. Description =========== To query the attributes of an entity, applications set the id field of a struct :c:type:`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 error code when the id is invalid. .. _media-ent-id-flag-next: Entities can be enumerated by or'ing the id with the ``MEDIA_ENT_ID_FLAG_NEXT`` flag. The driver will return information about the entity with the smallest id strictly larger than the requested one ('next entity'), or the ``EINVAL`` error code if there is none. Entity IDs can be non-contiguous. Applications must *not* try to enumerate entities by calling MEDIA_IOC_ENUM_ENTITIES with increasing id's until they get an error. .. c:type:: media_entity_desc .. tabularcolumns:: |p{1.5cm}|p{1.7cm}|p{1.6cm}|p{1.5cm}|p{11.2cm}| .. flat-table:: struct media_entity_desc :header-rows: 0 :stub-columns: 0 :widths: 2 2 1 8 * - __u32 - ``id`` - - Entity ID, set by the application. When the ID is or'ed with ``MEDIA_ENT_ID_FLAG_NEXT``, the driver clears the flag and returns the first entity with a larger ID. Do not expect that the ID will always be the same for each instance of the device. In other words, do not hardcode entity IDs in an application. * - char - ``name``\ [32] - - Entity name as an UTF-8 NULL-terminated string. This name must be unique within the media topology. * - __u32 - ``type`` - - Entity type, see :ref:`media-entity-functions` for details. * - __u32 - ``revision`` - - Entity revision. Always zero (obsolete) * - __u32 - ``flags`` - - Entity flags, see :ref:`media-entity-flag` for details. * - __u32 - ``group_id`` - - Entity group ID. Always zero (obsolete) * - __u16 - ``pads`` - - Number of pads * - __u16 - ``links`` - - Total number of outbound links. Inbound links are not counted in this field. * - __u32 - ``reserved[4]`` - - Reserved for future extensions. Drivers and applications must set the array to zero. * - union { - (anonymous) * - struct - ``dev`` - - Valid for (sub-)devices that create a single device node. * - - __u32 - ``major`` - Device node major number. * - - __u32 - ``minor`` - Device node minor number. * - __u8 - ``raw``\ [184] - - * - } - Return Value ============ On success 0 is returned, on error -1 and the ``errno`` variable is set appropriately. The generic error codes are described at the :ref:`Generic Error Codes ` chapter. EINVAL The struct :c:type:`media_entity_desc` ``id`` references a non-existing entity.