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I'm pretty new to Linux so bear with me.

I have an emachines laptop (ugh) with FN + Left Arr / Right Arr brightness keys. These work perfectly fine in Windows but do not work in Xubuntu. What happens is the brightness level popup will appear as you would expect, but the brightness does not change at all, and the computer seems to lag pretty badly.

I have both acpi_video0 and intel_backlight in /sys/class/backlight. Modifying the acpi_video0/brightness or setting it with xbacklight doesn't do anything, and acpi_backlight=vendor in the kernel didn't fix it, either. Changing intel_backlight/brightness, however, does. So acpi clearly doesn't work.

My current fix is the following bash script which works just fine (although you have to change the permissions for /sys/class/backlight/intel_backlight/brightness on start up in /etc/rc.local, since it's obviously a protected file).


# This script modifies the brightness level.
curr=$(cat /sys/class/backlight/intel_backlight/brightness)
echo $next > /sys/class/backlight/intel_backlight/brightness`

Currently, I have it mapped like so:

  • Super+- to run /home/myusername/hb -50000 which decreases the brightness
  • Super+= to run /home/myusername/hb 50000 which increases the brightness

Anyway, all I want to do is remap the FN + Arrow keys to run this script. It doesn't work in the Settings -> Keyboard -> Application Shortcuts (which is how I set the current keys).

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