Radeon HD 5870 -- 6 screen support on GNU/Linux

Discussion created by matevz on Mar 9, 2011
Latest reply on Mar 31, 2011 by matevz
Can not get Radeon HD 5870 to work on more than 2 monitors with Catalyst-11.2 on Fedora 14 x86_64


I bought a Radeon HD 5870 eyefinity with 6 display ports card to drive a 6 monitor setup for online display of proton-proton collisions at CMS detector at CERN.

The box is Fedora 14, x86_64, with catalyst-11.2 drivers (installed from fusion repository).
To test the card before depployment I connected it to 4 1280x1024 screens via DP->DVI adapters. It works for two monitors, the other two get detected (as seen in Xorg.0.log) but then the driver decides that they are "not connected" and only uses the first two.
I tried with Xinerama, too ... but this seems irrelevant as the monitors get disabled already at X start-up.

In amdcccle the screens are visible (but disabled, it says the machine needs to be rebooted for changes to take effect). Does
amdcccle write to any other file than xorg.conf?
Can any options be passed to fglrx kernel module?

I can provide details (the config and the log) if there is any hope this setup might work. Also, if there is no hope to get 6-screen output working on GNU/Linux, please let me know as I have to find another solution very fast (2011 run of the LHC is approaching fast). Best, Matevz