Based on kernel version 6.11
. Page generated on 2024-09-24 08:21 EST
.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 | .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later .. c:namespace:: MC .. _media_ioc_enum_links: ************************** ioctl MEDIA_IOC_ENUM_LINKS ************************** Name ==== MEDIA_IOC_ENUM_LINKS - Enumerate all pads and links for a given entity Synopsis ======== .. c:macro:: MEDIA_IOC_ENUM_LINKS ``int ioctl(int fd, MEDIA_IOC_ENUM_LINKS, struct media_links_enum *argp)`` Arguments ========= ``fd`` File descriptor returned by :c:func:`open()`. ``argp`` Pointer to struct :c:type:`media_links_enum`. Description =========== To enumerate pads and/or links for a given entity, applications set the entity field of a struct :c:type:`media_links_enum` structure and initialize the struct :c:type:`media_pad_desc` and struct :c:type:`media_link_desc` structure arrays pointed by the ``pads`` and ``links`` fields. They then call the MEDIA_IOC_ENUM_LINKS ioctl with a pointer to this structure. If the ``pads`` field is not NULL, the driver fills the ``pads`` array with information about the entity's pads. The array must have enough room to store all the entity's pads. The number of pads can be retrieved with :ref:`MEDIA_IOC_ENUM_ENTITIES`. If the ``links`` field is not NULL, the driver fills the ``links`` array with information about the entity's outbound links. The array must have enough room to store all the entity's outbound links. The number of outbound links can be retrieved with :ref:`MEDIA_IOC_ENUM_ENTITIES`. Only forward links that originate at one of the entity's source pads are returned during the enumeration process. .. c:type:: media_links_enum .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| .. flat-table:: struct media_links_enum :header-rows: 0 :stub-columns: 0 :widths: 1 1 2 * - __u32 - ``entity`` - Entity id, set by the application. * - struct :c:type:`media_pad_desc` - \*\ ``pads`` - Pointer to a pads array allocated by the application. Ignored if NULL. * - struct :c:type:`media_link_desc` - \*\ ``links`` - Pointer to a links array allocated by the application. Ignored if NULL. * - __u32 - ``reserved[4]`` - Reserved for future extensions. Drivers and applications must set the array to zero. .. c:type:: media_pad_desc .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| .. flat-table:: struct media_pad_desc :header-rows: 0 :stub-columns: 0 :widths: 1 1 2 * - __u32 - ``entity`` - ID of the entity this pad belongs to. * - __u16 - ``index`` - Pad index, starts at 0. * - __u32 - ``flags`` - Pad flags, see :ref:`media-pad-flag` for more details. * - __u32 - ``reserved[2]`` - Reserved for future extensions. Drivers and applications must set the array to zero. .. c:type:: media_link_desc .. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| .. flat-table:: struct media_link_desc :header-rows: 0 :stub-columns: 0 :widths: 1 1 2 * - struct :c:type:`media_pad_desc` - ``source`` - Pad at the origin of this link. * - struct :c:type:`media_pad_desc` - ``sink`` - Pad at the target of this link. * - __u32 - ``flags`` - Link flags, see :ref:`media-link-flag` for more details. * - __u32 - ``reserved[2]`` - Reserved for future extensions. Drivers and applications must set the array to zero. 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 <gen-errors>` chapter. EINVAL The struct :c:type:`media_links_enum` ``id`` references a non-existing entity. |