How to enable trace output

[allenzhu]

I want to get a trace log when my camera running. So, I run the command: cat /sys/kernel/debug/tracing/trace,
but nothing.

Do you have any advice to me?

[WayneWWW]

Use “trace_printk” in the driver code and it will print into above.

[jose.morera]

Hi @allenzhu
Try running the following commands in the Jetson terminal to enable the V4L2 debug trace:

sudo su

echo 1 > /sys/kernel/debug/tracing/tracing_on
echo 30720 > /sys/kernel/debug/tracing/buffer_size_kb
echo 1 > /sys/kernel/debug/tracing/events/tegra_rtcpu/enable
echo 1 > /sys/kernel/debug/tracing/events/freertos/enable
echo 2 > /sys/kernel/debug/camrtc/log-level
echo > /sys/kernel/debug/tracing/trace

exit

Now, try using the command to obtain the log again:

sudo cat /sys/kernel/debug/tracing/trace

Jose Morera
Embedded Software Engineer at RidgeRun
Contact us: support@ridgerun.com
Developers wiki: https://developer.ridgerun.com
Website: www.ridgerun.com