Rework laptop battery/power optimization settings

system/roles/laptop/power/auto-cpufreq/power-profiles-daemon/scripts/power_monitor.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+
+BAT=$(echo /sys/class/power_supply/BAT*) # only supports single-battery systems
+BAT_STATUS="$BAT/status"
+BAT_CAP="$BAT/capacity"
+
+POWER_SAVE_PERCENT=50 # Enter power-save mode if on bat and below this capacity
+
+HAS_PERFORMANCE="$(powerprofilesctl list | grep performance)"
+
+# monitor loop
+prev=0
+while true; do
+	# read the current state
+	status="$(cat "$BAT_STATUS")"
+	capacity="$(cat "$BAT_CAP")"
+
+	if [[ $status == "Discharging" ]]; then
+		if [[ $capacity -le $POWER_SAVE_PERCENT ]]; then
+			profile="power-saver"
+		else
+			profile="balanced"
+		fi
+	else
+		if [[ -n $HAS_PERFORMANCE ]]; then
+			profile="performance"
+		else
+			profile="balanced"
+		fi
+	fi
+
+	# Set the new profile
+	if [[ $profile != $prev ]]; then
+		echo -en "Setting power profile to ${profile}\n"
+		powerprofilesctl set $profile
+		prev=$profile
+	fi
+
+	# wait for changes in status or capacity files
+	# i.e. for the next power change event
+	inotifywait -qq "$BAT_STATUS" "$BAT_CAP"
+done