How do I adjust display contrast and brightness in Ubuntu?

Question

How can I adjust the contrast and brightness of a monitor in Ubuntu if the drivers are just for Windows?

Is there software that can do it without having to use the graphic drivers?

Answer 1

Is it an LCD monitor? You can try this from the command line:

$sudo echo -n 100 > /proc/acpi/video/VGA/LCD/brightness

If it's too bright use a lower number. If you have GLX instead of VGA the file is /proc/acpi/video/GLX0/LCD/brightness.

Answer 2

It would really help to know what sort of laptop you have, which video card, which monitor and whether you are on Gnome/KDE.

If you are using Gnome, the Gnome Color Manager could be a solution (not available with all gnome versions).

If you are using KDE with LCD, the luminosity applet KLcdDimmer might be a solution.

The gamma level may be adjustable with the xgamma command (not available with all video cards).

If you are using nvidia, you could edit ~/.nvidia-settings-rc, and call nvidia-settings --load-config-only.

For sony vaio the brightness and volume function keys may exist with installing fsfn.

You can search for a better video driver for your card on X.Org. Some of them have a bundled utility to adjust gamma/contrast/brightness.

Answer 3

My Dell 13z laptop won't allow me to increase the brightness when in a Linux distro. Ubuntu is convinced that it's already at maximum brightness.

I can however change it (using the Fn key combo) while BIOS is loading, so at least I don't need to boot into Windows to do it.

Answer 4

Use

sudo setpci -s 00:02.0 F4.B=xx

Where xx is the desired brightness in hexadecimal ranging from 00 (brightest) to FF (no brightness at all).

Answer 5

There is a workaround that might work for you in this bug report. This relies on adding acpi_osi=Linux to the kernel boot option. Others seems to have more success with these options: nomodeset acpi_backlight=vendor

These options can be passed via Grub. You might want to try them out by editing these commands in the Grub menu before putting it in Grub's configuration file.