May 15, 2021 2 minutes minutes read Admin

Update on X220 processor regulation

Update on processor regulation to limit temperature problems

The processor in my Thinkpad X220 is an Intel i5-2520M (4) @ 3,200GHz, so I don't need to use the acpi-cpufreq module, but the built-in intel-pstate module.

From the Arch Linux Wiki:

Note: The intel_pstate driver only supports two governors: powersave and performance. Although they share the same name as the generic governors, they do not work in the same way as the latter. The two intel_pstate governors provide dynamic scaling similar to that of the generic schedutil or ondemand governors. The performance governor provided by intel_pstate should give better power saving functionality than the old ondemand governor.

So I installed cpupower in addition to thermald:

sudo pacman -S cpupower cpupower-gui 
sudo systemctl enable cpupower
sudo systemctl start cpupower

I've found that my computer starts up with pstate=passive. To enable it on startup I added:

GRUB_CMDLINE_LINUX_DEFAULT="intel_pstate=active ...

in /etc/default/grub and run sudo update-grub.

I also edited /etc/default/cpupower with :


but I want the governor to be "powersave" when I'm running on battery, so I've written a script that is run by crontab, with cpupower as setuid root

*/1 * * * * /home/philip/.local/bin/power-adapt > /dev/null 2>&1

The script:

#!/bin/sh # put the governor in powersave mode if it is disconnected from the mains. ACPI=`acpi -a | cut -d ' ' -f 3` if [ "$ACPI" == "off-line" ] ; then cpupower frequency-set -g powersave; else cpupower frequency-set -g performance ; fi


I didn't like the idea of polling every second, so I wrote an udev rule instead:


ACTION=="change",SUBSYSTEM=="power_supply",RUN+="/usr/bin/bash /home/philip/.local/bin/power-adapt"

Also, when you reboot to battery, the default is "performance", so I added to .i3/config:
# set the right startup power settings

exec --no-startup-id ~/.local/bin/power-adapt