I have an unusual use case. I wonder if anyone can help. We use a PC with 8 HDMI outputs for powering a video wall in an operations centre. We use two Matrox video cards, each with 4 outputs. "lspci" reports these cards as" [AMD/ATI] Cape Verde PRO [FirePro W600]". On an older version of CentOS 7, I used the proprietary AMD/ATI driver. This had a utility (I roorget the name) that generated a working xorg.conf file. I could them throw up the "matchbox-window-manager" on each monitor in turn using "DISPLAY=:0.0", "DISPLAY=:0.1" etc and then throw up a full-screen chrome web browser in kiosk mode on each monitor after that. This all worked great. In a recent version of CentOS 7, this all broke. The proprietary driver no longer works. The good news is that the open source driver seems to work fine with multi-monitor in Gnome for example. My only issue is that I don't want to use Gnome across multiple monitors. I want to use matchbox-window-manager or similar, and specify individual X screen (":0.0", ":0.1" etc). How do I generate an xorg.conf file with the new open source drivers? Am I doing this all wrong? Thanks!