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Diffstat (limited to 'Documentation/media/uapi/v4l/vidioc-log-status.rst')
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diff --git a/Documentation/media/uapi/v4l/vidioc-log-status.rst b/Documentation/media/uapi/v4l/vidioc-log-status.rst new file mode 100644 index 000000000..bbeb7b5f5 --- /dev/null +++ b/Documentation/media/uapi/v4l/vidioc-log-status.rst @@ -0,0 +1,49 @@ +.. -*- coding: utf-8; mode: rst -*- + +.. _VIDIOC_LOG_STATUS: + +*********************** +ioctl VIDIOC_LOG_STATUS +*********************** + +Name +==== + +VIDIOC_LOG_STATUS - Log driver status information + + +Synopsis +======== + +.. c:function:: int ioctl( int fd, VIDIOC_LOG_STATUS) + :name: VIDIOC_LOG_STATUS + + +Arguments +========= + +``fd`` + File descriptor returned by :ref:`open() <func-open>`. + + +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. |