[deliverable/linux.git] / Documentation / linux_tv / media / v4l / vidioc-log-status.rst

.. -*- coding: utf-8; mode: rst -*-

.. _VIDIOC_LOG_STATUS:

***********************
ioctl VIDIOC_LOG_STATUS
***********************

*man VIDIOC_LOG_STATUS(2)*

Log driver status information


Synopsis
========

.. cpp:function:: int ioctl( int fd, int request )

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

As the video/audio devices become more complicated it becomes harder to
debug problems. When this ioctl is called the driver will output the
current device status to the kernel log. This is particular useful when
dealing with problems like no sound, no video and incorrectly tuned
channels. Also many modern devices autodetect video and audio standards
and this ioctl will report what the device thinks what the standard is.
Mismatches may give an indication where the problem is.

This ioctl is optional and not all drivers support it. It was introduced
in Linux 2.6.15.


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.


.. ------------------------------------------------------------------------------
.. This file was automatically converted from DocBook-XML with the dbxml
.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
.. from the linux kernel, refer to:
..
.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
.. ------------------------------------------------------------------------------
Commit	Line	Data
5377d91f MH	1	.. -- coding: utf-8; mode: rst --
5377d91f MH	2
af4a4d0d	3	.. _VIDIOC_LOG_STATUS:
5377d91f MH	4
	5	***********************
	6	ioctl VIDIOC_LOG_STATUS
	7	***********************
	8
	9	man VIDIOC_LOG_STATUS(2)
	10
	11	Log driver status information
	12
	13
	14	Synopsis
	15	========
	16
b7e67f6c	17	.. cpp:function:: int ioctl( int fd, int request )
5377d91f MH	18
	19	Description
	20	===========
	21
	22	As the video/audio devices become more complicated it becomes harder to
	23	debug problems. When this ioctl is called the driver will output the
	24	current device status to the kernel log. This is particular useful when
	25	dealing with problems like no sound, no video and incorrectly tuned
	26	channels. Also many modern devices autodetect video and audio standards
	27	and this ioctl will report what the device thinks what the standard is.
	28	Mismatches may give an indication where the problem is.
	29
	30	This ioctl is optional and not all drivers support it. It was introduced
	31	in Linux 2.6.15.
	32
	33
	34	Return Value
	35	============
	36
	37	On success 0 is returned, on error -1 and the ``errno`` variable is set
	38	appropriately. The generic error codes are described at the
	39	:ref:`Generic Error Codes <gen-errors>` chapter.
	40
	41
	42	.. ------------------------------------------------------------------------------
	43	.. This file was automatically converted from DocBook-XML with the dbxml
	44	.. library (https://github.com/return42/sphkerneldoc). The origin XML comes
	45	.. from the linux kernel, refer to:
	46	..
	47	.. * https://github.com/torvalds/linux/tree/master/Documentation/DocBook
	48	.. ------------------------------------------------------------------------------