How does the NanoPC-T4 Armbian system use the onboard PWM fan interface?

[laning]

I bought a NanoPC-T4 development board designed by friendlyelec and installed the Armbian operating system. But the heat generated by the Rk3399 main control chip is too high. I bought an official PWM fan. According to the official wiki, the fan can work normally. However, under the same configuration under Armbian, the fan can’t work normally, so I What work needs to be done? Thanks.

[laning]

https://wiki.friendlyelec.com/wiki/index.php/NanoPC-T4#Fan_speed_setting 

This is the official reference document for NanoPC-T4.

[c0rnelius]

Check to see if the following is available: ls /sys/devices/virtual/thermal/thermal_zone0/trip_point_4_temp

 

As long as the kernel has all the correct bits in place, you should then be able to choose a trip point for when you want the fan to start running.

 

Example

echo "55000" | sudo tee /sys/devices/virtual/thermal/thermal_zone0/trip_point_4_temp

 

 

[laning]

I found a workaround: install an older version of the kernel Armbian system, for example kernel version 4.4. But why it works this way, I don't know. So can someone tell me why?

[Igor]

2 hours ago, laning said:

for example kernel version 4.4. But why it works this way, I don't know. So can someone tell me why?

 

https://docs.armbian.com/User-Guide_FAQ/#why-does-hardware-feature-xy-work-in-old-kernel-but-not-in-more-recent-one

BTW. I have NanoPi M4V2 which by default comes with the fan. It works with Armbian out of the box, low rpm on idle, full on full load, when temp go up. So the problem is configuration.

[usual user]

Mainline DTB has proper thermal zone configuration. The kernel can manage its temperature management on its own, there is no need for an error-prone userspace component to be involved. As long as the kernel binary has build all the necessary drivers, it works out-of-the-box.

[laning]

You are right. I'm a beginner and recently learned what DTS does. I think if I want to operate in a new version of the kernel system, I need to configure the kernel compilation file to make it work properly.