For unknown (anyway, for my side) reason, the NVIDIA driver is not well configured after installation on the Samsung R580. In fact, brightness control does not work, with Fn+Keys or using the brightness applet, telling back to you that "Brightness status can not be read in Bios side".

So, in only one line, the issue can be solved: just edit the /etc/X11/xorg.conf file and add the following line (the bold one)  into the Device section:

Section "Device"

  Identifier "Default Device"

  Driver "nvidia"

  Option "NoLogo" "True"

  Option "RegistryDwords" "EnableBrightnessControl=1"

EndSection

And that's it ! Brightness control with Fn+keys is working great.

thanks to this forum entry (end of page) : http://ubuntuforums.org/archive/index.php/t-1357776.html
 

Have fun !

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