Troubleshooting Tips and Tricks

The following commands can be used to isolate and analyze issues:

Kernel Version

  • To Retrieve the Kernel Version use:

$ uname -r

Enable LibRealSense Log

  • To change the log level of LibRealSense logger, you need to set a local variable named LRS_LOG_LEVEL and initialize it with the desirable log level:

On Linux:

$ export LRS_LOG_LEVEL="<Log Level>"

On Windows:

$ set LRS_LOG_LEVEL="<Log Level>"

  • A LibRealSense log will be created even when an application does not activate the LibRealSense logger.

Connected Intel Cameras

  • To list all connected Intel Cameras:

$ lsusb | grep 8086

General Linux Kernel Log

  • To retrieve the last Linux Kernel log messages with timestamps:

$ dmesg -T

-To monitor the Linux Kernel log messages when there any change

$ dmesg -wH

  • To clear the dmesg buffer:

$ sudo dmesg -c

  • Linux writes all OS logs to /var/log folder.
    To review the entire kernel log file, use:

$ less /var/log/kern.log

UVC Video Module Traces

You can get more verbose logs from the uvcvideo kernel-module.
These logs can be seen in dmesg

  • To enable the UVC driver verbose log:

$ sudo echo 0xFFFF > /sys/module/uvcvideo/parameters/trace

  • To disable the UVC verbose log, replace 0xFFFF with 0.

For example, once enabled you will get the following line inside dmesg for each frame received from USB:

[619003.810541] uvcvideo: frame 1 stats: 0/0/1 packets, 0/0/1 pts (!early initial), 0/1 scr, last pts/stc/sof 25177741/25178007/81
[619003.810546] uvcvideo: Frame complete (FID bit toggled).
[619003.810556] uvcvideo: frame 2 stats: 0/0/1 packets, 0/0/1 pts (!early initial), 0/1 scr, last pts/stc/sof 25210903/25211168/346
[619003.810588] uvcvideo: uvc_v4l2_poll
[619003.811173] uvcvideo: uvc_v4l2_poll
[619003.843768] uvcvideo: frame 3 stats: 0/0/1 packets, 0/0/1 pts (!early initial), 0/1 scr, last pts/stc/sof 25210903/25211168/346
[619003.843774] uvcvideo: Frame complete (FID bit toggled).
[619003.843785] uvcvideo: frame 4 stats: 0/0/1 packets, 0/0/1 pts (!early initial), 0/1 scr, last pts/stc/sof 25244064/25244330/612

Kernel Events

  • To listen to camera connect/disconnect events:

$ sudo udevadm monitor

System Calls and Signals

  • To get a verbose log of all calls an application makes to the kernel, run the application under strace:

$ strace <Application Path>

Core Dump File

In case of a crash (for example SEGFAULT), a snapshot of the crash can be created (Core Dump) and submitted for inspection.

  1. Enable the auto-creation of Core Dump files:

$ ulimit -c unlimited

  1. Run the application that causes the crash

  2. Search for the core file in the current directory

Note: Auto-creation of the dump file will only work on the same Terminal that you ran the ulimit command.