Macbook Pro late 2011 screen brightness issue

Question

The keys to set the screen brightness work properly but everytime I reboot, the screen brightness is reverted to 100%, which is very annoying.

I've already tried to add the following lines to /etc/rc.local but with no success (only the keyboard backlight stays off):

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

echo '1' > /sys/devices/platform/applesmc.768/leds/smc::kbd_backlight/brightness

echo '6' > /sys/class/backlight/acpi_video0/brightness

rfkill block bluetooth

exit 0`

This worked for me when I was using Ubuntu 12.04 and also did after the upgrade to 12.10 but then after rebooting the screen brightness always reverted to 100%. Would be nice if anyone knows how to fix this.

My device: Macbook Pro 13" Late 2011

Thanks in advance!

Answer 1

Please do double check to see if that directory exists.
You can do so by repeatedly going deeper into the directory using cd and ls.
For instance, cd /sys would get you into the /sys directory and ls would list whatever is in it.
For me, the above mentioned brightness controls are in /sys/class/backlight/apple_backlight/brightness, so in my case, its echo '5' > /sys/class/backlight/apple_backlight/brightness