Macbook Pro boots with full screen brightness and keyboard backlight

Question

I have dual-booted my Macbook Pro with Ubuntu 12.04 . Whenever i log-in to Ubuntu, it does so with full screen brightness and keyboard backlight at full . How do i get rid of this? How can i tweak the start-up setting for screen brightness and disable keyboard backlight at start-up?

Solution 1

On my 11.2 MacBook Pro running Ubuntu 13.10, I got satisfactory results with this command, which makes an upstart task to dim them upon starting the login screen:

sudo cat > /etc/init/mbp-save-battery.conf << EOF
description "Lower screen and keyboard backlight brightness on boot"

task

start on login-session-start

script
  # lower screen brightness
  echo "35" > /sys/class/backlight/acpi_video0/brightness

  # Somebody else turns on the keyboard backlight
  # Wait for them before turning it off.
  sleep 1
  echo "0" > /sys/class/leds/smc\:\:kbd_backlight/brightness
end script
EOF

The sleep for the keyboard backlight control is not ideal, but it has worked every time for me.

Solution 2

To fix the screen brightness on my Macbook I stopped the apple_bl kernel module from being loaded. This seem to fix this for me.

1. Create a file called: /etc/modprobe.d/blacklist-applebl.conf

2. In the above file add the line:

    blacklist apple_bl
   

3. Reboot.

Solution 3

Keyboard backlight is only partially implemented, I think. It's working for unity, but in KDE there's no UI for it. You can manually change the keyboard backlight brightness on the command line. I don't have a mac, so I'm not sure what the exact command is, but for my samsung, the command is

echo 5 > /sys/class/leds/samsung\:\:kbd_backlight/brightness

(you have to do this as root, you can use sudo -s)

For the mac, have a look in /sys/class/leds, and see what's there.

Comments

[naught101]

see also askubuntu.com/questions/137355/…

[hektor]

I tried this, but it still reboots with maximum brightness.

[hektor]

Yep i can use the keys to control the brightness.

[Eliah Kagan]

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[cgmb]

I should note that the keyboard backlight occasionally turns itself back on. Not sure what causes that.