Troubleshooting Q&A

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Summary of all questions:

• Q: How to retrieve my Linux kernel version?
• Q: How do I enable librealsense logs?
• Q: How do I see which Intel RealSense cameras are connects?
• Q: How do I view the general Linux kernel log?
• Q: How do I view the Linux UVC video module traces?
• Q: How do I view the Linux kernel events
• Q: How do I view Linux system calls and signals
• Q: How do I get core dump files?

Q: How to retrieve my Linux kernel version?

Type the following in your shell:

$ uname -r

Q: How do I enable librealsense logs?

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:

Linux:

$ export LRS_LOG_LEVEL="<Log Level>"

Windows:

$ set LRS_LOG_LEVEL="<Log Level>"

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

Q: How do I see which Intel RealSense cameras are connects?

Linux:

Open shell:

$ lsusb | grep 8086

Windows:

1. Click the Win-Key+X keys
2. Choose Device Manager
3. Look under Imaging devices for "Intel RealSense" cameras

Q: How do I view the general Linux kernel log?

To retrieve the last Linux Kernel log messages with timestamps:

$ dmesg -T

• 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

Q: How do I view the Linux 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

Q: How do I view the Linux kernel events

• To listen to camera connect/disconnect events:

$ sudo udevadm monitor

Q: How do I view Linux 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>

Q: How do I get core dump files?

Linux:

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

2. Run the application that causes the crash

3. 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.

Windows:

Follow this guide: How to generate a complete crash dump file or a kernel crash dump file by using an NMI on a Windows-based system