I have had the pleasure of working in the Linux realm for the past 15 years and on several occasions I have found myself specifying multi-head video cards. The first few times that I evaluated the two primary vendors ATI and Nvidia, Nvidia came out on top because of the stability of their Linux drivers. Since that time I have gone back to take a second and third look and as a company, we have started porting our graphics centric code from Cuda to OpenCL in order to support multiple vendors.
Hardware providers tend to partner with either ATI or Nvidia so if a company wants to be a software company, you really need to support both vendors. That said, if your host OS is Linux you may be in for a rough ride.
I would have to say that based on today’s evaluation of the ATI Linux driver that porting to OpenCL may be a waste of time. I setup an ATI HD6800 Series video card in Ubuntu Linux 12.04LTS today and I could not get three monitors to work. The software discovered the three monitors when I used the DVI and HDMI ports, but the display port couldn’t even detect what was connected. I could not mirror displays and when I setup multiple displays only the two connected to the DVI ports would consistently work.
I can understand that the market for more than a dual head system is not that great, but there are some of us that need that functionality. Nvidia seems to be able to consistently make their software work so what’s up ATI ?