1 .. SPDX-License-Identifier: GFDL-1.1-no-invari 1 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
2 .. c:namespace:: V4L 2 .. c:namespace:: V4L
3 3
4 .. _VIDIOC_SUBDEV_G_CLIENT_CAP: 4 .. _VIDIOC_SUBDEV_G_CLIENT_CAP:
5 5
6 ********************************************** 6 ************************************************************
7 ioctl VIDIOC_SUBDEV_G_CLIENT_CAP, VIDIOC_SUBDE 7 ioctl VIDIOC_SUBDEV_G_CLIENT_CAP, VIDIOC_SUBDEV_S_CLIENT_CAP
8 ********************************************** 8 ************************************************************
9 9
10 Name 10 Name
11 ==== 11 ====
12 12
13 VIDIOC_SUBDEV_G_CLIENT_CAP - VIDIOC_SUBDEV_S_C 13 VIDIOC_SUBDEV_G_CLIENT_CAP - VIDIOC_SUBDEV_S_CLIENT_CAP - Get or set client
14 capabilities. 14 capabilities.
15 15
16 Synopsis 16 Synopsis
17 ======== 17 ========
18 18
19 .. c:macro:: VIDIOC_SUBDEV_G_CLIENT_CAP 19 .. c:macro:: VIDIOC_SUBDEV_G_CLIENT_CAP
20 20
21 ``int ioctl(int fd, VIDIOC_SUBDEV_G_CLIENT_CAP 21 ``int ioctl(int fd, VIDIOC_SUBDEV_G_CLIENT_CAP, struct v4l2_subdev_client_capability *argp)``
22 22
23 .. c:macro:: VIDIOC_SUBDEV_S_CLIENT_CAP 23 .. c:macro:: VIDIOC_SUBDEV_S_CLIENT_CAP
24 24
25 ``int ioctl(int fd, VIDIOC_SUBDEV_S_CLIENT_CAP 25 ``int ioctl(int fd, VIDIOC_SUBDEV_S_CLIENT_CAP, struct v4l2_subdev_client_capability *argp)``
26 26
27 Arguments 27 Arguments
28 ========= 28 =========
29 29
30 ``fd`` 30 ``fd``
31 File descriptor returned by :ref:`open() < 31 File descriptor returned by :ref:`open() <func-open>`.
32 32
33 ``argp`` 33 ``argp``
34 Pointer to struct :c:type:`v4l2_subdev_cli 34 Pointer to struct :c:type:`v4l2_subdev_client_capability`.
35 35
36 Description 36 Description
37 =========== 37 ===========
38 38
39 These ioctls are used to get and set the clien 39 These ioctls are used to get and set the client (the application using the
40 subdevice ioctls) capabilities. The client cap 40 subdevice ioctls) capabilities. The client capabilities are stored in the file
41 handle of the opened subdev device node, and t 41 handle of the opened subdev device node, and the client must set the
42 capabilities for each opened subdev separately 42 capabilities for each opened subdev separately.
43 43
44 By default no client capabilities are set when 44 By default no client capabilities are set when a subdev device node is opened.
45 45
46 The purpose of the client capabilities are to 46 The purpose of the client capabilities are to inform the kernel of the behavior
47 of the client, mainly related to maintaining c 47 of the client, mainly related to maintaining compatibility with different
48 kernel and userspace versions. 48 kernel and userspace versions.
49 49
50 The ``VIDIOC_SUBDEV_G_CLIENT_CAP`` ioctl retur 50 The ``VIDIOC_SUBDEV_G_CLIENT_CAP`` ioctl returns the current client capabilities
51 associated with the file handle ``fd``. 51 associated with the file handle ``fd``.
52 52
53 The ``VIDIOC_SUBDEV_S_CLIENT_CAP`` ioctl sets 53 The ``VIDIOC_SUBDEV_S_CLIENT_CAP`` ioctl sets client capabilities for the file
54 handle ``fd``. The new capabilities fully repl 54 handle ``fd``. The new capabilities fully replace the current capabilities, the
55 ioctl can therefore also be used to remove cap 55 ioctl can therefore also be used to remove capabilities that have previously
56 been set. 56 been set.
57 57
58 ``VIDIOC_SUBDEV_S_CLIENT_CAP`` modifies the st 58 ``VIDIOC_SUBDEV_S_CLIENT_CAP`` modifies the struct
59 :c:type:`v4l2_subdev_client_capability` to ref 59 :c:type:`v4l2_subdev_client_capability` to reflect the capabilities that have
60 been accepted. A common case for the kernel no 60 been accepted. A common case for the kernel not accepting a capability is that
61 the kernel is older than the headers the users 61 the kernel is older than the headers the userspace uses, and thus the capability
62 is unknown to the kernel. 62 is unknown to the kernel.
63 63
64 .. tabularcolumns:: |p{1.5cm}|p{2.9cm}|p{12.9c <<
65 <<
66 .. c:type:: v4l2_subdev_client_capability <<
67 <<
68 .. flat-table:: struct v4l2_subdev_client_capa <<
69 :header-rows: 0 <<
70 :stub-columns: 0 <<
71 :widths: 3 4 20 <<
72 <<
73 * - __u64 <<
74 - ``capabilities`` <<
75 - Sub-device client capabilities of the <<
76 <<
77 .. tabularcolumns:: |p{6.8cm}|p{2.4cm}|p{8.1cm <<
78 <<
79 .. flat-table:: Client Capabilities 64 .. flat-table:: Client Capabilities
80 :header-rows: 1 65 :header-rows: 1
81 66
82 * - Capability 67 * - Capability
83 - Description 68 - Description
84 * - ``V4L2_SUBDEV_CLIENT_CAP_STREAMS`` 69 * - ``V4L2_SUBDEV_CLIENT_CAP_STREAMS``
85 - The client is aware of streams. Settin 70 - The client is aware of streams. Setting this flag enables the use
86 of 'stream' fields (referring to the s 71 of 'stream' fields (referring to the stream number) with various
87 ioctls. If this is not set (which is t 72 ioctls. If this is not set (which is the default), the 'stream' fields
88 will be forced to 0 by the kernel. 73 will be forced to 0 by the kernel.
89 * - ``V4L2_SUBDEV_CLIENT_CAP_INTERVAL_USES <<
90 - The client is aware of the :c:type:`v4 <<
91 ``which`` field. If this is not set (w <<
92 ``which`` field is forced to ``V4L2_SU <<
93 kernel. <<
94 74
95 Return Value 75 Return Value
96 ============ 76 ============
97 77
98 On success 0 is returned, on error -1 and the 78 On success 0 is returned, on error -1 and the ``errno`` variable is set
99 appropriately. The generic error codes are des 79 appropriately. The generic error codes are described at the
100 :ref:`Generic Error Codes <gen-errors>` chapte 80 :ref:`Generic Error Codes <gen-errors>` chapter.
101 81
102 ENOIOCTLCMD 82 ENOIOCTLCMD
103 The kernel does not support this ioctl. 83 The kernel does not support this ioctl.
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