[mirror_ubuntu-artful-kernel.git] / Documentation / media / uapi / v4l / vidioc-log-status.rst

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

.. _VIDIOC_LOG_STATUS:

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

Name
====

VIDIOC_LOG_STATUS - Log driver status information


Synopsis
========

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


Arguments
=========


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.
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
15e7d615	9	Name
586027ce	10	====
5377d91f	11
586027ce	12	VIDIOC_LOG_STATUS - Log driver status information
5377d91f	13
15e7d615 MCC	14
15e7d615 MCC	15	Synopsis
5377d91f MH	16	========
5377d91f MH	17
b7e67f6c	18	.. cpp:function:: int ioctl( int fd, int request )
5377d91f	19
586027ce	20
15e7d615	21	Arguments
586027ce MCC	22	=========
	23
	24
	25
15e7d615	26	Description
5377d91f MH	27	===========
	28
	29	As the video/audio devices become more complicated it becomes harder to
	30	debug problems. When this ioctl is called the driver will output the
	31	current device status to the kernel log. This is particular useful when
	32	dealing with problems like no sound, no video and incorrectly tuned
	33	channels. Also many modern devices autodetect video and audio standards
	34	and this ioctl will report what the device thinks what the standard is.
	35	Mismatches may give an indication where the problem is.
	36
	37	This ioctl is optional and not all drivers support it. It was introduced
	38	in Linux 2.6.15.
	39
	40
15e7d615	41	Return Value
5377d91f MH	42	============
	43
	44	On success 0 is returned, on error -1 and the ``errno`` variable is set
	45	appropriately. The generic error codes are described at the
	46	:ref:`Generic Error Codes <gen-errors>` chapter.