I'm trying to set up a triple monitor display, but can't seem to figure out what to do next. The three monitors work as a single stretched desktop in Windows XP with little setup configuration, so I expected to boot into Slackware (KDE) and it would just work. But it doesn't.
Here is the relevant output of 'lspci':
01:05.0 VGA compatible controller: Cirrus Logic GD 5446
02:00.0 VGA compatible controller: ATI Technologies Inc RV620 LE [Radeon HD 3450]
By default the two 'radeon monitors' come up, and I can configure them to work perfectly. In the BIOS, if I set the PCI-E as the 'Primary display', Slackware shows the desktop on the cirrus monitor only.
In both cases, xrandr shows only the monitors currently displaying.
My question is: What steps should I take now to try and enable a triple monitor setup?
EDIT: I just realised that if I have the PCI output setup as the default output in the BIOS, the Linux system boots up with all 3 screens. The X display appears on the PCI output, and and the other two monitors show console login prompts. Interestingly, if I login on the console and enter 'startx', it starts a new X server on a new virtual console. I can access these via CTRL+ALT+(anything above 7); below 7 it switches to the console on the other two monitors. Whats going on?!?!?!