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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?

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What about the contrast? – Georg Schölly Sep 7 '10 at 21:48
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. – Kenny Rasschaert Sep 7 '10 at 21:56

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.

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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.

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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).

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Just a few hours ago, I installed Quantal Quetzal Ubuntu, I just went to dash home and typed "settings" and selected the Power Settings, then clicked the "Brightness Settings" link and finally adjust the desired brightness.

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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.

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@Bruno is right. I experienced the same problem when using Fedora 17. The keyboard hotkeys for brightness would not have any change on the brightness. Do a simple edit of your grub file as explained at

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Welcome to Super User! Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference. – Canadian Luke Aug 13 '12 at 22:57

If you are using Ubuntu go to System > Preferences > Power management there you find a brightness bar slider set it to the desired brightness level and to keep the change permanent check on the Make default check box

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