I have just installed Ubuntu 13.10 and am trying to adjust my laptop screen brightness. My laptop Dell studio 1558 has a key to change the screen brightness; however, when I reduced brightness to zero the actual brightness didn't change at all. This causes my battery to run out quickly.

I have tried the 'brightness and lock' in Ubuntu, but of no use.

Is there any software which really makes a change in brightness?


if i understand your post correctly this is because the brightness hotkeys do not work? if so try changing:


to this:

GRUB_CMDLINE_LINUX="quiet splash acpi_osi=Linux acpi_backlight=vendor"

in the file /etc/default/grub, then:

sudo -i update-grub

after this hotkeys should be functional

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In Dell studio the current brightness level is stored as a text in the following file /sys/class/backlight/intel_backlight/brightness.

One way to reduce brightness is to open that file as superuser and change the brightness level. The level has some maximum value above which an increase in the level will not affect the brightness of the screen.

Edit the value in the above file using the command line editor - nano. run the following command in the terminal

sudo nano /sys/class/backlight/intel_backlight/brightness

put in a password and then replace the value in the file with a lower value.

press 'Ctrl+x' to exit and 'Y' when prompted to save changes. the hit Enter and then boom.... good-luck

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  • I have a Dell XPS L401X and I just upgraded to ubuntu 18.04 few days back. This solution helped me fix the brightness problem. It would really great if manual task can somehow be scripted, so that the brightness can be altered more conveniently. – Sâu Sep 14 '19 at 12:09

This may well have something to do with your graphics card. Do you have NVIDIA?

I've had the same problem; it was due to the Nouveau graphics card driver that Ubuntu installs as a default.

Open 'Software & Updates' and go to the tab 'Additional drivers'. It will tell you which graphics card driver it is using. Switch to NVIDIA's recommended proprietary driver. Reboot, and adjusting brightness should now work.

Be alerted: the new driver will mess up your nice splash screen in the beginning, but apart from that, everything will run fine.

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I too faced this problem with my ASUS laptop until I found this.There is a simple command to fix this brightness problem.Open the terminal and type in it this command:

sudo setpci -s 00:02.0 F4.B=1f

and enter your password if it asks for.

Now note the last thing in here "1f",it gives the brightness on a hexadecimal scale (00-ff) where 00 is the least brightness and ff is the maximum brightness.

Hope it helps.

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