mirror of https://gitee.com/openkylin/linux.git
57 lines
1.4 KiB
ReStructuredText
57 lines
1.4 KiB
ReStructuredText
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
|
|
.. c:namespace:: DTV.fe
|
|
|
|
.. _FE_SET_TONE:
|
|
|
|
*****************
|
|
ioctl FE_SET_TONE
|
|
*****************
|
|
|
|
Name
|
|
====
|
|
|
|
FE_SET_TONE - Sets/resets the generation of the continuous 22kHz tone.
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. c:macro:: FE_SET_TONE
|
|
|
|
``int ioctl(int fd, FE_SET_TONE, enum fe_sec_tone_mode tone)``
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :c:func:`open()`.
|
|
|
|
``tone``
|
|
an integer enumered value described at :c:type:`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.
|
|
|
|
Return Value
|
|
============
|
|
|
|
On success 0 is returned.
|
|
|
|
On error -1 is returned, and the ``errno`` variable is set
|
|
appropriately.
|
|
|
|
Generic error codes are described at the
|
|
:ref:`Generic Error Codes <gen-errors>` chapter.
|