When I started to work with Jetson TX1 I used JetPack 2.0
Fan worked according current heat dissipation.
After some time of work on a system made by JetPack 2.1 I found my Jetson overheated because fan has stopped.
I have checked a fresh system, Fan works.
Now I have installed a new JetPack 2.2.1 and started a sample… Fan does not work. System is overheating and go slow down…
The only way to make it work is to type:
sudo echo 255 > /sys/kernel/debug/tegra_fan/target_pwm