54f38fcae5
Since 2017, there is an space reserved for userspace API,
created by changeset 1d596dee38 ("docs: Create a user-space API guide").
As the media subsystem was one of the first subsystems to use
Sphinx, until this patch, we were keeping things on a separate
place.
Let's just use the new location, as having all uAPI altogether
will likely make things easier for developers.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
62 lines
1.5 KiB
ReStructuredText
62 lines
1.5 KiB
ReStructuredText
.. Permission is granted to copy, distribute and/or modify this
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.. document under the terms of the GNU Free Documentation License,
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.. Version 1.1 or any later version published by the Free Software
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.. Foundation, with no Invariant Sections, no Front-Cover Texts
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.. and no Back-Cover Texts. A copy of the license is included at
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.. Documentation/userspace-api/media/fdl-appendix.rst.
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..
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.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
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.. _VIDIOC_OVERLAY:
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********************
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ioctl VIDIOC_OVERLAY
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********************
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Name
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====
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VIDIOC_OVERLAY - Start or stop video overlay
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Synopsis
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========
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.. c:function:: int ioctl( int fd, VIDIOC_OVERLAY, const int *argp )
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:name: VIDIOC_OVERLAY
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Arguments
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=========
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``fd``
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File descriptor returned by :ref:`open() <func-open>`.
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``argp``
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Pointer to an integer.
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Description
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===========
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This ioctl is part of the :ref:`video overlay <overlay>` I/O method.
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Applications call :ref:`VIDIOC_OVERLAY` to start or stop the overlay. It
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takes a pointer to an integer which must be set to zero by the
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application to stop overlay, to one to start.
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Drivers do not support :ref:`VIDIOC_STREAMON` or
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:ref:`VIDIOC_STREAMOFF <VIDIOC_STREAMON>` with
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``V4L2_BUF_TYPE_VIDEO_OVERLAY``.
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Return Value
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============
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On success 0 is returned, on error -1 and the ``errno`` variable is set
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appropriately. The generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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EINVAL
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The overlay parameters have not been set up. See :ref:`overlay`
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for the necessary steps.
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