linux/Documentation/media/uapi/dvb/ca-set-descr.rst
Mauro Carvalho Chehab bd9049edc6 media: ca docs: document CA_SET_DESCR ioctl and structs
The av7110 driver uses CA_SET_DESCR to store the descrambler
control words at the CA descrambler slots.

Document it.

Thanks-to: Honza Petrouš <jpetrous@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-09-05 06:23:07 -04:00

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.. -*- coding: utf-8; mode: rst -*-
.. _CA_SET_DESCR:
============
CA_SET_DESCR
============
Name
----
CA_SET_DESCR
Synopsis
--------
.. c:function:: int ioctl(fd, CA_SET_DESCR, struct ca_descr *desc)
:name: CA_SET_DESCR
Arguments
---------
``fd``
File descriptor returned by a previous call to :c:func:`open() <cec-open>`.
``msg``
Pointer to struct :c:type:`ca_descr`.
Description
-----------
CA_SET_DESCR is used for feeding descrambler CA slots with descrambling
keys (refered as control words).
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.