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I tried changing the brightness but it won't dim or brighten using keys or going under applications, it just stays the same.

user301958
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  • 3

2 Answers2

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Check which graphics driver is used to control the brightness

ls /sys/class/backlight/

if it responds with a list that includes intel_backlight proceed - if not, I can't help you

If you have the intel_backlight then

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

Add the lines

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

Logout, and log back in - your backlight should work now. I got this answer from itsfoss.com

Charles Green
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For me works: (Lenovo B590, Linux Mint 17)

Amar Prabhu said: (at www.itsfoss.com/fix-brightness-ubuntu-1310/#comment-1362036392)

For those who this fix did not work (it didnt for me), do the following:

Update your Grub file, line no 11 in /etc/default/grub to

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

update grub using the command

update-grub

Reboot and you are done.

HOW TO fix backlight/brightness:

https://wiki.archlinux.org/index.php/Intel_Graphics#Backlight_is_not_adjustable

HOW TO change GRUB parameters:

https://wiki.archlinux.org/index.php/Kernel_parameters#GRUB

guest
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  • The above solution can cause in many cases grub to not load Ubuntu at all! I had the same problem with brightness and this solution prevented my laptop from loading the system. Be extra careful with this solution and be sure you know how to undo it while you are inside grub. Check here: http://askubuntu.com/questions/498628/ubuntu-12-04-kernel-3-13-0-30/500812#500812 – orestis Jul 23 '14 at 22:18