手動控制風扇轉速 (IBM X220)

# vi /etc/modprobe.d/thinkpad_acpi.conf

thinkpad_acpi fan_control=1

# reboot

$ cat /proc/acpi/ibm/fan

level:        auto

$ echo level 0 | sudo tee /proc/acpi/ibm/fan  # fan off

$ echo level 2 | sudo tee /proc/acpi/ibm/fan  # low speed

$ echo level 4 | sudo tee /proc/acpi/ibm/fan  # medium speed

$ echo level 7 | sudo tee /proc/acpi/ibm/fan  # maximum speed 

$ echo level auto | sudo tee /proc/acpi/ibm/fan  # automatic - default

# echo level disengaged | sudo tee /proc/acpi/ibm/fan  # disengaged

References :
How to control fan speed - ThinkWiki