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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>
84 lines
2.2 KiB
ReStructuredText
84 lines
2.2 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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.. _FE_GET_PROPERTY:
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**************************************
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ioctl FE_SET_PROPERTY, FE_GET_PROPERTY
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**************************************
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Name
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====
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FE_SET_PROPERTY - FE_GET_PROPERTY - FE_SET_PROPERTY sets one or more frontend properties. - FE_GET_PROPERTY returns one or more frontend properties.
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Synopsis
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========
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.. c:function:: int ioctl( int fd, FE_GET_PROPERTY, struct dtv_properties *argp )
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:name: FE_GET_PROPERTY
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.. c:function:: int ioctl( int fd, FE_SET_PROPERTY, struct dtv_properties *argp )
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:name: FE_SET_PROPERTY
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Arguments
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=========
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``fd``
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File descriptor returned by :ref:`open() <frontend_f_open>`.
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``argp``
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Pointer to struct :c:type:`dtv_properties`.
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Description
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===========
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All Digital TV frontend devices support the ``FE_SET_PROPERTY`` and
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``FE_GET_PROPERTY`` ioctls. The supported properties and statistics
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depends on the delivery system and on the device:
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- ``FE_SET_PROPERTY:``
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- This ioctl is used to set one or more frontend properties.
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- This is the basic command to request the frontend to tune into
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some frequency and to start decoding the digital TV signal.
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- This call requires read/write access to the device.
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.. note::
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At return, the values aren't updated to reflect the actual
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parameters used. If the actual parameters are needed, an explicit
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call to ``FE_GET_PROPERTY`` is needed.
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- ``FE_GET_PROPERTY:``
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- This ioctl is used to get properties and statistics from the
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frontend.
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- No properties are changed, and statistics aren't reset.
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- This call only requires read-only access to the device.
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Return Value
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============
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On success 0 is returned.
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On error -1 is returned, and the ``errno`` variable is set
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appropriately.
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Generic error codes are described at the
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:ref:`Generic Error Codes <gen-errors>` chapter.
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