Strange problem with fan speed (ACPI?)

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sancho_sk

Member
Dec 9, 2022
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I encountered a weird problem with my Proxmox VE installation.
To explain - I bought ultra-cheap miniPC from Aliexpress. The model is GMKtech NucBox5.
The BIOS is quite excessive to configure - I've never seen so many options. However, I configured the fan trip points to 71 degrees C to run fan at 100% and 60 degrees C to stop the fan completely.
And it works OK when I boot Ubuntu from USB key or install Debian. So far so good.
The PC does not create any ACPI points for lm-sensors to detect (only CPU, chipset and disk temps are reported).
However, the fan spins up and down in line with the BIOS config no problem.
Later, I installed latest proxmox. Everything works, but I noticed the fan does not spin up at all. The CPU reached 91 degrees C and started to heavily throttle down. At the same time the plugged-in USB key got so hot I could not even touch it.
After 2-3 minutes when the fan still did not spool and the CPU was still running at 90 degrees, the box got so hot I could no longer touch it.
I shut the machine down, let it cool and booted Ubuntu from USB stick - all OK, when not doing anything, the fans spool down, when starting browsing or similar activity, the fans would spool up.
I have never seen such behavior. I am not sure what to search for - it seems to me like the kernel handles the temperature management differently than other kernels (both Ubuntu and Debian work OK). Is there some sysctl setting or something I can enable to fix this problem, perhaps?
 
Hi, this seems like a thermal driver issue with the PVE kernel — the fan control logic relies on ACPI/DPTF modules that aren’t loaded by default in Proxmox.

Ubuntu and Debian use a generic kernel that includes these power-management hooks, so BIOS fan control still works there.

Try booting with the Debian kernel (apt install linux-image-amd64). This installs Debian’s stock kernel alongside your existing PVE kernel.

I could be wrong but worth a try.
 
Thanks for the suggestion.
I loaded the debian kernel 6.12.48+deb13-amd64, but the behavior is the same - if I reboot the machine while CPU is cool, the fan will always be off and (right now) the CPU reached 96 degrees already). If I reboot it while hot, the fan will turn on during BIOS and will stay on even when the CPU goes to 39 degrees :(
I feel like I am missing something. Perhaps some specific ACPI settings that debian/ubuntu does by default, but proxmox does not?
 
sancho_sk said:
Thanks for the suggestion.
I loaded the debian kernel 6.12.48+deb13-amd64, but the behavior is the same - if I reboot the machine while CPU is cool, the fan will always be off and (right now) the CPU reached 96 degrees already). If I reboot it while hot, the fan will turn on during BIOS and will stay on even when the CPU goes to 39 degrees :(
I feel like I am missing something. Perhaps some specific ACPI settings that debian/ubuntu does by default, but proxmox does not?
Click to expand...
Can you try this?

Try installing on your Proxmox node:

Code: 
apt install thermald acpid
systemctl enable --now thermald acpid

Reboot and check if /sys/class/thermal/ updates dynamically

See if it works after.
 
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