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author | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-08 11:40:06 -0300 |
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committer | Mauro Carvalho Chehab <mchehab@s-opensource.com> | 2016-07-08 11:59:40 -0300 |
commit | 60c2820d0f6d3497975b6488e2599f8f611d8b95 (patch) | |
tree | b3b03707c6438ea9b99cc57e847ebf517f968ab1 /Documentation/media/uapi/v4l/vidioc-enum-dv-timings.rst | |
parent | a97369b5e21ea9b8b5fef7c0f4f48bbe60c07ca3 (diff) | |
download | linux-60c2820d0f6d3497975b6488e2599f8f611d8b95.tar.bz2 |
doc_rst: rename the media Sphinx suff to Documentation/media
The name of the subsystem is "media", and not "linux_tv". Also,
as we plan to add other stuff there in the future, let's
rename also the media uAPI book to media_uapi, to make it
clearer.
No functional changes.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-enum-dv-timings.rst')
-rw-r--r-- | Documentation/media/uapi/v4l/vidioc-enum-dv-timings.rst | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/Documentation/media/uapi/v4l/vidioc-enum-dv-timings.rst b/Documentation/media/uapi/v4l/vidioc-enum-dv-timings.rst new file mode 100644 index 000000000000..f0dd0c4ca7d0 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-enum-dv-timings.rst @@ -0,0 +1,119 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_ENUM_DV_TIMINGS: + +*********************************************************** +ioctl VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS +*********************************************************** + +Name +==== + +VIDIOC_ENUM_DV_TIMINGS - VIDIOC_SUBDEV_ENUM_DV_TIMINGS - Enumerate supported Digital Video timings + + +Synopsis +======== + +.. cpp:function:: int ioctl( int fd, int request, struct v4l2_enum_dv_timings *argp ) + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + +``request`` + VIDIOC_ENUM_DV_TIMINGS, VIDIOC_SUBDEV_ENUM_DV_TIMINGS + +``argp`` + + +Description +=========== + +While some DV receivers or transmitters support a wide range of timings, +others support only a limited number of timings. With this ioctl +applications can enumerate a list of known supported timings. Call +:ref:`VIDIOC_DV_TIMINGS_CAP` to check if it +also supports other standards or even custom timings that are not in +this list. + +To query the available timings, applications initialize the ``index`` +field, set the ``pad`` field to 0, zero the reserved array of struct +:ref:`v4l2_enum_dv_timings <v4l2-enum-dv-timings>` and call the +``VIDIOC_ENUM_DV_TIMINGS`` ioctl on a video node with a pointer to this +structure. Drivers fill the rest of the structure or return an ``EINVAL`` +error code when the index is out of bounds. To enumerate all supported +DV timings, applications shall begin at index zero, incrementing by one +until the driver returns ``EINVAL``. Note that drivers may enumerate a +different set of DV timings after switching the video input or output. + +When implemented by the driver DV timings of subdevices can be queried +by calling the ``VIDIOC_SUBDEV_ENUM_DV_TIMINGS`` ioctl directly on a +subdevice node. The DV timings are specific to inputs (for DV receivers) +or outputs (for DV transmitters), applications must specify the desired +pad number in the struct +:ref:`v4l2_enum_dv_timings <v4l2-enum-dv-timings>` ``pad`` field. +Attempts to enumerate timings on a pad that doesn't support them will +return an ``EINVAL`` error code. + + +.. _v4l2-enum-dv-timings: + +.. flat-table:: struct v4l2_enum_dv_timings + :header-rows: 0 + :stub-columns: 0 + :widths: 1 1 2 + + + - .. row 1 + + - __u32 + + - ``index`` + + - Number of the DV timings, set by the application. + + - .. row 2 + + - __u32 + + - ``pad`` + + - Pad number as reported by the media controller API. This field is + only used when operating on a subdevice node. When operating on a + video node applications must set this field to zero. + + - .. row 3 + + - __u32 + + - ``reserved``\ [2] + + - Reserved for future extensions. Drivers and applications must set + the array to zero. + + - .. row 4 + + - struct :ref:`v4l2_dv_timings <v4l2-dv-timings>` + + - ``timings`` + + - The timings. + + +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 :ref:`v4l2_enum_dv_timings <v4l2-enum-dv-timings>` + ``index`` is out of bounds or the ``pad`` number is invalid. + +ENODATA + Digital video presets are not supported for this input or output. |