The function keys to control the screen brightness - Fn-F11 & Fn-F12 - are not working.

Xubuntu 18.10.

Dell Inspiron 17 7000 (7786) laptop

I have tried updating the boot parameters in /etc/default/grub

Currently running: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset acpi_osi=! "acpi_osi=Windows 2015""

I also tried these options: "acpi_osi=" "acpi_osi=Linux"

Some more checks:

ls -l /sys/class/backlight

...shows nothing.

xrandr --verbose | grep Bright

...shows nothing.

sudo showkey

...shows 224 for Fn-F11 (brightness down) and 225 for Fn-F12 (brightness up).

The other function keys - volume, keyboard backlight, wireless on/off, etc... are working OK.


This solution worked for me:

Taken from:

Brightness fn key shortcut doesn't work on ASUS laptop


13.10 Can't Adjust Dell Laptop Backlight

...but not the same.

1. Create file: /usr/share/X11/xorg.conf.d/20-intel.conf

Open terminal and type these commands:

sudo touch /usr/share/X11/xorg.conf.d/20-intel.conf

sudo nano /usr/share/X11/xorg.conf.d/20-intel.conf

Add the following lines to this file:

Section "Device"
    Identifier  "card0"
    Driver      "intel"
    Option      "Backlight"  "intel_backlight"
    BusID       "PCI:0:2:0"

Save the file and close nano.

2. Update Grub settings

In a terminal and type these commands:

sudo nano /etc/default/grub

find the line starting with:


and add the option "acpi_backlight=vendor" (without the quotes).

E.g.: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Save the file and exit nano.

In a in terminal:

sudo update-grub

Restart your laptop and it will work probably...

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