Re: Dual-head with TwinView but need fullscreen for games
I have a 5900 with 2 CRT monitors attached (a 17" and a 19"). All you need to do is define some more metamodes. I'm assuming your default desktop is 1280x1024 (which X sees as one screen with a resolution of 2560x1024, with nVidia's built-in Xinerama extension handling the details of where to put windows and dialogs and stuff -- the key is that X sees one big screen, not two).
Anyway, the key to getting games and stuff to display properly on only ONE monitor is telling the driver when to shut off the second one. Here is what I do, since I only run my desktop in 1280x1024 (bearing in mind it should all be on one line, even if the forum breaks it here):
Option "MetaModes" "1280x1024, 1280x1024; NULL, 1152x864; NULL, 1024x768; NULL, 800x600; NULL, 640x480"
as opposed to yours:
Option "MetaModes" "1280x1024,1280x1024; 1024x768,1024x768"
At 1280x1024, both my monitors are on. At the lower resolutions, my first monitor is turned off and the game can have the entire second screen all to itself. I've had problems before with "TwinViewOrientation" "LeftOf" causing problems like you describe (half the image on one monitor, the other monitor either just blank or powered down), so you might have better luck if you try a "RightOf" orientation (since your monitors have the same refresh rates, you could just physically switch the inputs).
To test it, fire up Tuxracer, which runs at 640x480 and one of your monitors should turn off and Tuxracer should fire up fullscreen on the other one. I haven't found a way to game fullscreen on one monitor while having the second one display anything useful (like in Windows), I guess because in TwinView mode X doesn't realize there ARE two screens.