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 »


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

thanks to this forum entry (end of page) :

Have fun !