amd_laptop_undervolt/powersave.sh

#!/bin/sh

GOVERNOR="powersave"
apply_lm=true

while getopts 'hopPg:' opt; do
	case $opt in
		'h')
			echo "Usage: powersave [-hopP] [-g governor]"
			echo "    -h  this message"
			echo "    -o  set governor to ondemand and activate laptop mode"
			echo "    -p  set governor to powersave and activate laptop mode (default)"
			echo "    -P  set governor to performance"
			echo "    -g governor  set governor to the specified value"
			exit 0
			;;
		'o')
			GOVERNOR=ondemand
			apply_lm=true
			;;
		'p')
			GOVERNOR=powersave
			apply_lm=true
			;;
		'P')
			GOVERNOR=performance
			apply_lm=false
			;;
		'g')
			GOVERNOR=$OPTARG
			apply_lm=false
			;;
		'?'|*) ;;
	esac
done
shift $((OPTIND-1))

# set governor
CPUS="$(nproc)"
for c in $(seq 0 $((CPUS-1)))
do
	echo $GOVERNOR > /sys/devices/system/cpu/"cpu$c"/cpufreq/scaling_governor
	printf '[cpu %d] %s\n' "$c" "$(cat "/sys/devices/system/cpu/cpu$c/cpufreq/scaling_governor")"
done


if $apply_lm; then
	# "5 is a sensible time" https://www.kernel.org/doc/Documentation/laptops/laptop-mode.txt
	sysctl 'vm.laptop_mode=5'
else
	# disable laptop_mode
	sysctl 'vm.laptop_mode=0'
fi