MEDIA_IOC_ENUM_ENTITIES — Enumerate entities and their properties
int ioctl( | int fd, |
| int request, | |
struct media_entity_desc *argp); |
To query the attributes of an entity, applications set the id field of a struct 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.
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.
Table L.8. struct media_entity_desc
| __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. | ||
| char | name[32] | Entity name as an UTF-8 NULL-terminated string. | ||
| __u32 | type | Entity type, see Table 16.1, “Media entity types” for details. | ||
| __u32 | revision | Entity revision. Always zero (obsolete) | ||
| __u32 | flags | Entity flags, see Table 16.2, “Media entity flags” 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. | ||
| union | ||||
| 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] |
On success 0 is returned, on error -1 and the errno variable is set appropriately. The generic error codes are described at the Generic Error Codes chapter.
The struct media_entity_desc id references
a non-existing entity.