I was just handed a 2nd monitor for my system at work, and using Centos 5 (latest) can't make dual head work. a good bit of googling isn't being particularly helpful either.
It's a HP workstation xw4100, with Nvidia Quadro NVS280SD graphics card. Enabling dual head in the "display" app simply configures X so that it (i.e., X) won't start. I haven't found the x log file in /var/log to be helpful, either. This is using the legacy 96.x.x driver from Nvidia.
the NvidiaDetect app (from epel) says it should be using a newer driver than the 96.x.x (forgot which one, exactly) but when attempting to install it I get a msg that the card requires a 96.x.x driver.
browsing to nvidia.com and entering the model numbers into their driver finder app gives another newer version that also gives the same result. So it looks like I'm stuck with the 96.x.x driver.
some googling indicates a few people have made it work, but none of their methods are working for me.
I was beginning to wonder if the hardware even supported dual head, so I booted up a Fedora 17 LIVE CD. it initializes both monitors with no action from me at all, with a desktop spanning the two screens, just fine. It must be using the Nouveau driver (which, AFAIK, can't be used on Centos 5), so still the issue could either be spanning/dual head doesn't work with the ancient nvidia driver, or we (neither me, nor the tools on Centos) knows how to configure it.
Clues would be appreciated. thanks in advance!