adding additional PWR Energy Savings

[rudiratlos]

I've wrote a script that uses some tweaks to bring power consumption further down. Maybe you will find it usefull and use parts of the code (enable_pwrsave) directly in your startup script. It's only: /usr/bin/tvservice -o > /dev/null /usr/bin/cpufreq-set -g powersave additionally you have to:

1. install the sw-package cpufrequtils
2. add some parameters to /boot/config.txt this is done by calling the script with parameter setup (pls. see function setup_env)

calling the script with parameter status: this will show the active cpu freq. set by the cpu governor

e.g. current CPU frequency is 600 MHz (asserted by call to hardware).

have fun regards Stefan

`#/bin/bash

V1.0 by SF 2022-07-27

inspired by: https://buyzero.de/blogs/news/raspberry-pi-strom-sparen-tipps-tricks

function setup_env { fn="/boot/config.txt" tm="# define minimum freq. for energy saving (used by cpu governor)" grep -Fq "$tm" "$fn" _ret=$? if [ "$_ret" != "0" ]; then if [ "$1" != "noswpkg" ]; then apt-get -qy update apt-get -qy install cpufrequtils fi echo " " >> $fn echo "# Disable the PWR LED (save energy)" >> $fn echo "dtparam=pwr_led_trigger=none" >> $fn echo "dtparam=pwr_led_activelow=off" >> $fn echo "$tm" >> $fn echo "# use turbo speed for 20sec to speed up boot process" >> $fn echo "initial_turbo=20" >> $fn echo "force_turbo=0" >> $fn echo "arm_freq_min=250" >> $fn echo "core_freq_min=100" >> $fn echo "sdram_freq_min=150" >> $fn echo "over_voltage_min=0" >> $fn fi return 0 }

function enable_pwrsave {

enable pwr save, LEDs off, HDMI port off, set cpu to lower freq

echo 0 | tee /sys/class/leds/led0/brightness > /dev/null

echo 0 | tee /sys/class/leds/led1/brightness > /dev/null

/usr/bin/tvservice -o > /dev/null /usr/bin/cpufreq-set -g powersave _ret=$? return $_ret }

function disable_pwrsave {

disable pwr save, LEDs on, HDMI port on, set cpu to higher freq

echo 1 | tee /sys/class/leds/led0/brightness > /dev/null

echo 1 | tee /sys/class/leds/led1/brightness > /dev/null

/usr/bin/tvservice -p > /dev/null /usr/bin/cpufreq-set -g performance _ret=$? return $_ret }

ret=0 case "$1" in setup) setup_env "$2" ret=$? ;; start) enable_pwrsave "$2" ret=$? ;; stop) disable_pwrsave "$2" ret=$? ;; status) /usr/bin/cpufreq-info "$2" ret=$? ;; ) echo "Usage: ${0##/} start | stop | status | setup [noswpkg]" esac

exit $ret`