#!/bin/sh
# A script to enable laptop power saving features

# List of modules to unload, space seperated. Edit depending on your hardware and preferences.
modlist="uvcvideo"

# Bus list for runtime pm.
buslist="pci spi i2c"

# Enable some power saving settings while on battery

case "$1" in
    true)

#hdparm settings
hdparm -B 1 -S 60 /dev/sda

# Intel audio power saving
echo Y > /sys/module/snd_hda_intel/parameters/power_save_controller
echo 1 > /sys/module/snd_hda_intel/parameters/power_save

#Enable multi core power savings
echo 1 > /sys/devices/system/cpu/sched_smt_power_savings

#Enable laptop mode
echo 5 > /proc/sys/vm/laptop_mode

#Keep dirty writes in memory – non scrive sul disco finchè il 90% della memoria è piena: la predefinita di pm-utils è 60 noi la settiamo a 90
echo 90 > /proc/sys/vm/dirty_ratio

# Keep dirty writes out of cache – Quando arriva al valore impostato sopra, svuota la cache fino al valore impostato qui
echo 1 > /proc/sys/vm/dirty_background_ratio

# Writeback 10 min – ogni quanto si attiva il demone per scrivere su disco se la memoria non si riempie mai al valore impostato a dirty_ratio
echo 60000 > /proc/sys/vm/dirty_writeback_centisecs

#Imposta la frequenza dei processori su conservative
cpufreq-set -r -g conservative

#Fa in modo che i programmi che hanno un bassa priorità non causino l'incremento della frequenza  vale solo se la policy è conservative o ondemand, cioè con frequenza variabile. Con powersave che tiene sempre il processore al minimo non serve.
echo 1 > /sys/devices/system/cpu/cpufreq/conservative/ignore_nice_load

# Set backlight brightness
echo 1 >  /sys/class/backlight/acpi_video0/brightness

# wireless powersave
iwconfig wlan0 power on
iwconfig wlan0 power timeout 500ms

# disable ethernet on battery
ifconfig eth0 down

# i915
#echo 1 > /sys/module/i915/parameters/i915_enable_rc6
#echo 1 > /sys/module/i915/parameters/i915_enable_fbc
#echo 1 > /sys/module/i915/parameters/lvds_downclock

# Disable nmi watchdog
echo 0 > /proc/sys/kernel/nmi_watchdog

# Swappiness
echo 9 > /proc/sys/vm/swappiness &


# USB powersaving
        for i in /sys/bus/usb/devices/*/power/autosuspend; do
            echo 1 > $i
        done
for i in /sys/bus/usb/devices/*/power/level; do echo auto > $i; done

# SATA power saving
        for i in /sys/class/scsi_host/host*/link_power_management_policy; do
            echo min_power > $i
        done

#Disable hardware modules to save power
        for mod in $modlist; do
            grep $mod /proc/modules >/dev/null || continue
            modprobe -r $mod 2>/dev/null
        done

# Enable runtime power management.
        for bus in $buslist; do
            for i in /sys/bus/$bus/devices/*/power/control; do
                echo auto > $i
            done
        done

 ;;
    false)

 #Return settings to default on AC power

hdparm -B 128 -S 0 /dev/sda
echo N > /sys/module/snd_hda_intel/parameters/power_save_controller
echo 0 > /sys/module/snd_hda_intel/parameters/power_save
echo 0 > /sys/devices/system/cpu/sched_smt_power_savings
echo 0 > /proc/sys/vm/laptop_mode
echo 10 > /proc/sys/vm/dirty_ratio
echo 5 > /proc/sys/vm/dirty_background_ratio
echo 500 > /proc/sys/vm/dirty_writeback_centisecs
cpufreq-set -r -g ondemand
echo 0 > /sys/devices/system/cpu/cpufreq/conservative/ignore_nice_load
echo 13 >  /sys/class/backlight/acpi_video0/brightness
iwconfig wlan0 power off
ifconfig eth0 up
#echo 0 > /sys/module/i915/parameters/i915_enable_rc6
#echo 0 > /sys/module/i915/parameters/i915_enable_fbc
#echo 0 > /sys/module/i915/parameters/lvds_downclock
echo 1 > /proc/sys/kernel/nmi_watchdog
echo 60 > /proc/sys/vm/swappiness
for i in /sys/bus/usb/devices/*/power/autosuspend; do
            echo 2 > $i
        done
for i in /sys/bus/usb/devices/*/power/level; do echo on > $i; done
for i in /sys/class/scsi_host/host*/link_power_management_policy
            do echo max_performance > $i
 done

for mod in $modlist; do
            if ! lsmod | grep $mod; then
                modprobe $mod 2>/dev/null
            fi
        done

         for bus in $buslist; do
            for i in /sys/bus/$bus/devices/*/power/control; do
                echo on > $i
            done
        done
    ;;
esac

exit 0