powersave

#!/bin/sh
# A script to enable laptop power saving features for #! & Debian GNU+linux.
# http://crunchbanglinux.org/forums/topic/11954

# List of modules to unload, space seperated. Edit depending on your hardware and preferences.
#modlist="usb_storage"
# Bus list for runtime pm. Probably shouldn't touch this.
buslist="pci spi i2c"

case "$1" in
    true)
       # USB powersaving
        for i in /sys/bus/usb/devices/*/power/autosuspend; do
            echo 1 > $i
        done
       # intel hda powersave
        echo Y > /sys/module/snd_hda_intel/parameters/power_save_controller
        echo 1 > /sys/module/snd_hda_intel/parameters/power_save

       # 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. Suggested by powertop.
        for bus in $buslist; do
            for i in /sys/bus/$bus/devices/*/power/control; do
                echo auto > $i
            done
        done
    echo 5 > /sys/class/backlight/acpi_video0/brightness
    ;;
    false)
        for i in /sys/bus/usb/devices/*/power/autosuspend; do
            echo 2 > $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
    echo 15 > /sys/class/backlight/acpi_video0/brightness
    echo N > /sys/module/snd_hda_intel/parameters/power_save_controller
    echo 0 > /sys/module/snd_hda_intel/parameters/power_save
    ;;
esac

exit 0