intelBrightness

#!/bin/bash
# We really need bash functionality

if [[ "$EUID" -ne 0 ]]; then
  sudo "$0" $@
  exit 0
fi

function getCurrentBrightness()
{
    local result=`intel_reg read BLC_PWM_PCH_CTL2 | awk '{print $3}'`
    #echo "Current register value is: ${result}"
    result=`echo $((16#${result:2}))`
    result=$((${result}-61407232));
    echo "${result}"
}

if [[ $1 = "currentValue" ]]; then
 echo "$(getCurrentBrightness)"
 exit 0
fi

if [[ $1 = "backup" ]]; then
 currentValue=`intel_reg read BLC_PWM_PCH_CTL2 | awk '{print $3}'`
 echo "${currentValue}" > /tmp/backupBrightness
 exit 0
fi

if [[ $1 = "restore" ]]; then
 currentValue=`cat /tmp/backupBrightness`
 # set new value
 intel_reg write BLC_PWM_PCH_CTL2 "${currentValue}"
 # enable manual brightnes control
 intel_reg write BLC_PWM_PCH_CTL1 0xc0000000
 exit 0
fi

case $1 in
    plus)
	currentValueInt=$(getCurrentBrightness)
	currentValueInt=$((currentValueInt+47));
	;;
    minus)
	currentValueInt=$(getCurrentBrightness)
	currentValueInt=$((currentValueInt-47));
	;;
    *)
	currentValueInt=$1;
	;;
esac

if ! [[ "${currentValueInt}" -ge "0" ]] ; then
 currentValueInt=0
elif ! [[ "937" -ge "${currentValueInt}" ]] ; then
 currentValueInt=937
fi

  (echo -n "${currentValueInt}" > /sys/class/backlight/intel_backlight/actual_brightness) 2> /dev/null

  currentValueInt=$((${currentValueInt}+61407232));

  valueToSet=0x`echo "obase=16; ${currentValueInt}" | bc`

  echo "Setting new value: ${valueToSet}"

  # set new value
  intel_reg write BLC_PWM_PCH_CTL2 "${valueToSet}"

  # enable manual brightnes control
  intel_reg write BLC_PWM_PCH_CTL1 0xc0000000