In FC2 I was successfully using my ATI FireGL Z1 dual DVI card to drive two Viewsonic VP201s monitors with the open source Xorg driver.
I just upgraded to FC3 and according to the Xorg logs it seems to detect and initialize my second monitor but nothing ever displays on it. The monitor tells me "Out of Range" and that half of the desktop appears in my Workplace Switcher applet but I can't drag apps that start on that half to the visible half.
I've tried running 'system-config-display' with no xorg.conf file and it wasn't able to generate a configuration. When I was done selecting the dual monitor options and tried to click "OK" it just sat there.
Anyone else have this configuration or see similar behavior with a dual- head display setup? I haven't checked out the Xorg mailing lists yet but that is my next stop....
I had problems with dual head configuration, but only attached comments to a bugzilla entry.
I have a different (older) ATI card and nothing is displayed on it when used as a secondary card. (815 internal as primary).
Going the other way and using the ATI as primary and the 815 as secondary cause overlapping I/O for the two graphics controllers. It is a real mess.
Anyway, here is a bugzilla entry that another person entered.
I believe that with removing the xorg.conf file, then running s-c-display, I was able to get dual head xorg.conf files, though they were not setup to my desires. Your problem sounds a bit different though. Removing the xorg.conf fle should have at least allowed you to create a new file.
The bug that I experienced is below:
I hope an upgrade is made soon for this problem. A bug report for the ill behaviour that you are seeing might be good to submit for FC3.
-- God help the troubadour who tries to be a star. The more that you try to find success, the more that you will fail. -- Phil Ochs, on the Second System Effect