Ubuntu – Macbook starts with the screen on minimum brightness

backlightmacbook

I have a Macbook2,1 with Ubuntu 12.04. When I start the computer the back light is on and I can see all of the boot stuff. Once the GUI begins to start up the backlight is turned completely off and I can not see anything. I do however hear the little ubuntu drum beat, can then type my password and log on. Once I have done this I can then use the brightness buttons to turn the brightness back up but the logon screen is always just blackness.

I can control the brightness from the command line using 

 echo 500 | sudo tee /sys/class/backlight/intel_video/brightness

and I put this line into /etc/rc.local before the exit 0 but this doesnt do anything.
How can I get the brightness back up when the GUI starts up?

Best Answer

The following worked for me:

  1. Find your ACPI interface: grep acpi_video /var/log/Xorg.0.log
  2. Get the desired brightness level: set brightness to desired level then run cat /sys/class/backlight/acpi_videoX/brightness, substituting X for the ACPI number found on step 1

  3. Create a fixbrightness.conf file: run gksu gedit /etc/init/fixbrightness.conf and paste the following, replacing BRIGHTNESS_VALUE with the number gotten from the previous step and X for your ACPI interface number:

    description "Sets brightness after graphics device is loaded"

start on graphics-device-added`
task
exec /bin/echo BRIGHTNESS_VALUE > /sys/class/backlight/acpi_videoX/brightness

  4. Save and reboot.

Source: http://www.webupd8.org/2014/10/fix-brightness-getting-reset-to-very.html

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