I have two monitors, which I have set up with nvidia-settings in Twinview. The result: When I want to do something in xRandR, it does not function. It doesn't report one output per video card head, but a single output mapped to the combined area of both monitors:
rumtscho@bradbury:~$ xrandr xrandr: Failed to get size of gamma for output default Screen 0: minimum 3840 x 1440, current 3840 x 1440, maximum 3840 x 1440 default connected 3840x1440+0+0 0mm x 0mm 3840x1440 50.0*
Now I promised somebody to help test a driver. The developer is using an open source driver for Intel video cards, and his driver assumes that there is more than one xRandR output, each mapped to a monitor. So I tried rewriting my xorg.conf to somehow get two outputs to show up, but failed. Googling showed that people faced with the xRandR-nvidia problem either stopped using xRandR and achieved what they needed with nvidia-settings, or changed their driver to nouveau.
The first is not going to help in my situation, and I am not willing to give up the proprietary driver, because Compiz won't work without it. So does anybody know a way to get nvidia to actually pass on information on outputs to xRandR?