For a long time I searched for a way to connect two monitors to an NVIDIA graphic card without using the proprietary nvidia driver (mainly because I wanted to try use OpenBSD and 64bit FreeBSD).
Somehow I never read nv’s (the free Xorg driver) man page – until today. And there it is, clear as crystal:
Option "Dualhead" "boolean" Enables simple VBE-based dual head mode. This sets the same resolution on both outputs and lays them out side-by-side. The screens will be panned together as one big metamode if the virtual desktop is larger than both screens combined.
So I just had to change my Xorg config from:
Section "Device" Identifier "Card0" Driver "nvidia" Option "TwinView" EndSection
Section "Device" Identifier "Card0" Driver "nv" Option "Dualhead" EndSection So simple!