xref: /openbmc/linux/Documentation/userspace-api/media/dvb/fe-get-info.rst (revision 54f38fca)

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.. document under the terms of the GNU Free Documentation License,
.. Version 1.1 or any later version published by the Free Software
.. Foundation, with no Invariant Sections, no Front-Cover Texts
.. and no Back-Cover Texts. A copy of the license is included at
.. Documentation/userspace-api/media/fdl-appendix.rst.
..
.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections

.. _FE_GET_INFO:

*****************
ioctl FE_GET_INFO
*****************

Name
====

FE_GET_INFO - Query Digital TV frontend capabilities and returns information
about the - front-end. This call only requires read-only access to the device.


Synopsis
========

.. c:function:: int ioctl( int fd, FE_GET_INFO, struct dvb_frontend_info *argp )
    :name: FE_GET_INFO


Arguments
=========

``fd``
    File descriptor returned by :ref:`open() <frontend_f_open>`.

``argp``
    pointer to struct struct
    :c:type:`dvb_frontend_info`


Description
===========

All Digital TV frontend devices support the :ref:`FE_GET_INFO` ioctl. It is
used to identify kernel devices compatible with this specification and to
obtain information about driver and hardware capabilities. The ioctl
takes a pointer to dvb_frontend_info which is filled by the driver.
When the driver is not compatible with this specification the ioctl
returns an error.


frontend capabilities
=====================

Capabilities describe what a frontend can do. Some capabilities are
supported only on some specific frontend types.

The frontend capabilities are described at :c:type:`fe_caps`.


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.