Laptop users still have the backlight issue in Ubuntu 14.04. Every time Ubuntu boots up you get the maximum level of screen brightness.
Here’s a workaround by adding a startup script which will automatically adjust screen brightness when Ubuntu boots up.
To get started:
Preparation: Open your file browser and navigate to “Computer→ sys → class → backlight” directory. You’ll see two or three folders there.
In each folder there’s a file called actual_brightness, you can see its content (brightness value) through the thumbnail icon.
Remember them and do:
- Change your screen brightness through Fn + Arrow key.
- Check out the actual_brightness files in each folder (Re-open each folder to refresh the value).
- Does the value change?
- Remember the folder name in which the value of actual_brightness changes.
- Replace acpi_video0 in below commands with that folder name
1. Press Ctrl+Alt+T on keyboard to open the terminal. When it opens, run the command below will give you the maximum level of your laptop backlight:
Mine is 9, so I can set backlight level from 0 to 9.
2. Run the command below one by one. You’ll get the super user privilege and open the /etc/rc.local file, a script executed at the end of each multiuser runlevel, with gedit editor.
Add the line below before the last. Change the number 0 to the brightness level you want.
echo 0 > /sys/class/backlight/acpi_video0/brightness
That’s it. Enjoy!