Samsung R480 laptop LCD brightness

Mendy got a Samsung R480 laptop but screen brightness did not work properly. Using KDE’s brightness slider caused the screen to flicker horribly and once you let go, it’s too dark. GNOME’s just doesn’t work at all.

After a suspend and resume with the Nouveau driver, the slider works properly, but only goes to half brightness at the maximum setting. It was possible to set the brightness manually via:
echo -n 60 > /proc/acpi/video/NVID/LCD/brightness

That was not suitable. So I switched to the NVIDIA driver, but the laptop brightness was immutable until I discovered a post with the solution. Simply adding the following to the Device section in /etc/X11/xorg.conf lets KDE control the brightness correctly, and perfectly. Great!
Section "Device"
Identifier "Videocard0"
Driver "nvidia"
Option "RegistryDwords" "EnableBrightnessControl=1"
Option "UseEdidDpi" "false"
Option "DPI" "96 x 96"

I also added the DPI option above to get 96×96 as some text was too large after switching to the NVIDIA driver. Fedora still suspends and resumes and everything is just perfect!

2 thoughts on “Samsung R480 laptop LCD brightness

  1. nightship

    Excellent advice!

    I suffered from the same problem: Could not adjust the screen brightness of my LCD display on my Lenovo ThinkPad T510 (using the respective Fn key combinations).

    I tried your hint and simply added the single line
    Option “RegistryDwords” “EnableBrightnessControl=1”
    to the “Device” section of file /etc/X11/xorg.conf. After a restart of the xserver / kdm, adjusting screen brightness using the function key combinations works perfectly. By the way, I’m running Kubuntu 10.04 LTS (lucid) with a 2.6.32-23 kernel.

    Thanks a lot! 🙂

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