Dual head not working, where to start?

Gregor Mosheh support at hostgis.com
Wed Nov 14 22:08:07 PST 2007

Hi, all. I hate to post a "it doesn't work" but here it is. :)

I'm running GNOME on Fedora 8, and am trying to get a multi-head setup 
working. My primary video card is some low-end Nvidia, and that's 
working A-OK. My secondary card is a ATI Radeon 7000 dual-head card (so, 
a total of 3 displays if I can pull this off).

Now, I've tried the usual tactic: I've gone into the Display panel, gone 
into the Dual Head tab, selected my Radeon and "spanning desktops", 
clicked OK, and rebooted. But the primary display it still the only one 
showing anything.

Where do I start on debugging this? Would my xorg.conf be helpful, or 
should I start someplace lower in the chain?

Other technical tidbits:

The other 2 monitors are still in power-save mode, indicating that 
nothing's trying to talk to them. Perhaps the problem is lower-level 
than xorg, kernel driver?

Running "modprobe radeon" in init 3, then going into init 5, did 
successfully load the module. But it has no effect on my problem.

If I remove the Nvidia card so the Radeon 7000 is the only display 
adapter, then the Radeon works fine with a single head. The card starts 
in clone mode through the BIOS screen, then goes into single-head mode 
later. Twiddling the Display / Dual Head panel later has no effect. So 
the Radeon 7000 does in fact work.

Gregor Mosheh / Greg Allensworth
System Administrator, HostGIS cartographic development & hosting services

"Remember that no one cares if you can back up,
  only if you can restore." - AMANDA

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