On my ThinkPad T470 which is a dual boot with Ubuntu 18.04 and Windows 10, everything was working fine in Ubuntu until after a while I needed to boot Windows. Since then, the fan on the laptop runs constantly at full speed on Ubuntu.
I have tried the common solutions such as setting acpi_osi=!Windows 2012 in the grub setting according to this answer or setting fan speed using thinkfan according to this answer.
I have also checked my BIOS setting, but every thing looks normal as some options are set for performance and some set to be balanced between performance, energy consumption, and fan noise. The problem is Ubuntu seems to not recognize the BIOS settings or any other settings for that matter.
None of the solutions above made any difference in the fan noise.
Any help would be appreciated.
EDIT: I am suspicious about ACPI not doing its job for some reason.
EDIT 2: One observation that may be worth mentioning is that the fan runs at normal/low speed when I boot the laptop and the grub menu prompts me to choose an operating system (Ubuntu or Windows) to continue with. Then the fan takes off to full speed as I choose Ubuntu. I think this means that BIOS settings work fine.
EDIT 3: Trying to use fancontrol according to this answer, after running sudo pwmconfig, I get the following message:
hwmon3/pwm1_enable stuck to 2
Manual control mode not supported, skipping hwmon3/pwm1.
There are no usable PWM outputs.