0001 .. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
0002 .. c:namespace:: V4L
0003
0004 .. _VIDIOC_LOG_STATUS:
0005
0006 ***********************
0007 ioctl VIDIOC_LOG_STATUS
0008 ***********************
0009
0010 Name
0011 ====
0012
0013 VIDIOC_LOG_STATUS - Log driver status information
0014
0015 Synopsis
0016 ========
0017
0018 .. c:macro:: VIDIOC_LOG_STATUS
0019
0020 ``int ioctl(int fd, VIDIOC_LOG_STATUS)``
0021
0022 Arguments
0023 =========
0024
0025 ``fd``
0026 File descriptor returned by :c:func:`open()`.
0027
0028 Description
0029 ===========
0030
0031 As the video/audio devices become more complicated it becomes harder to
0032 debug problems. When this ioctl is called the driver will output the
0033 current device status to the kernel log. This is particular useful when
0034 dealing with problems like no sound, no video and incorrectly tuned
0035 channels. Also many modern devices autodetect video and audio standards
0036 and this ioctl will report what the device thinks what the standard is.
0037 Mismatches may give an indication where the problem is.
0038
0039 This ioctl is optional and not all drivers support it. It was introduced
0040 in Linux 2.6.15.
0041
0042 Return Value
0043 ============
0044
0045 On success 0 is returned, on error -1 and the ``errno`` variable is set
0046 appropriately. The generic error codes are described at the
0047 :ref:`Generic Error Codes <gen-errors>` chapter.
