linux/Documentation/media/uapi/dvb/fe-set-tone.rst
Mauro Carvalho Chehab 706f8a9975 [media] doc-rst: improve display of notes and warnings
There are several notes and warning mesages in the middle of
the media docbook. Use the ReST tags for that, as it makes
them visually better and hightlights them.

While here, modify a few ones to make them clearer.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-07-10 12:06:28 -03:00

92 lines
1.8 KiB
ReStructuredText

.. -*- coding: utf-8; mode: rst -*-
.. _FE_SET_TONE:
*****************
ioctl FE_SET_TONE
*****************
Name
====
FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, enum fe_sec_tone_mode *tone )
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <frontend_f_open>`.
``request``
FE_SET_TONE
``tone``
pointer to enum :ref:`fe_sec_tone_mode <fe-sec-tone-mode>`
Description
===========
This ioctl is used to set the generation of the continuous 22kHz tone.
This call requires read/write permissions.
Usually, satellite antenna subsystems require that the digital TV device
to send a 22kHz tone in order to select between high/low band on some
dual-band LNBf. It is also used to send signals to DiSEqC equipment, but
this is done using the DiSEqC ioctls.
.. attention:: If more than one device is connected to the same antenna,
setting a tone may interfere on other devices, as they may lose the
capability of selecting the band. So, it is recommended that applications
would change to SEC_TONE_OFF when the device is not used.
.. _fe-sec-tone-mode-t:
enum fe_sec_tone_mode
=====================
.. _fe-sec-tone-mode:
.. flat-table:: enum fe_sec_tone_mode
:header-rows: 1
:stub-columns: 0
- .. row 1
- ID
- Description
- .. row 2
- .. _SEC-TONE-ON:
``SEC_TONE_ON``
- Sends a 22kHz tone burst to the antenna
- .. row 3
- .. _SEC-TONE-OFF:
``SEC_TONE_OFF``
- Don't send a 22kHz tone to the antenna (except if the
FE_DISEQC_* ioctls are called)
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.