1.. Permission is granted to copy, distribute and/or modify this
2.. document under the terms of the GNU Free Documentation License,
3.. Version 1.1 or any later version published by the Free Software
4.. Foundation, with no Invariant Sections, no Front-Cover Texts
5.. and no Back-Cover Texts. A copy of the license is included at
6.. Documentation/userspace-api/media/fdl-appendix.rst.
7..
8.. TODO: replace it to GFDL-1.1-or-later WITH no-invariant-sections
9
10.. _VIDIOC_LOG_STATUS:
11
12***********************
13ioctl VIDIOC_LOG_STATUS
14***********************
15
16Name
17====
18
19VIDIOC_LOG_STATUS - Log driver status information
20
21
22Synopsis
23========
24
25.. c:function:: int ioctl( int fd, VIDIOC_LOG_STATUS)
26    :name: VIDIOC_LOG_STATUS
27
28
29Arguments
30=========
31
32``fd``
33    File descriptor returned by :ref:`open() <func-open>`.
34
35
36Description
37===========
38
39As the video/audio devices become more complicated it becomes harder to
40debug problems. When this ioctl is called the driver will output the
41current device status to the kernel log. This is particular useful when
42dealing with problems like no sound, no video and incorrectly tuned
43channels. Also many modern devices autodetect video and audio standards
44and this ioctl will report what the device thinks what the standard is.
45Mismatches may give an indication where the problem is.
46
47This ioctl is optional and not all drivers support it. It was introduced
48in Linux 2.6.15.
49
50
51Return Value
52============
53
54On success 0 is returned, on error -1 and the ``errno`` variable is set
55appropriately. The generic error codes are described at the
56:ref:`Generic Error Codes <gen-errors>` chapter.
57