I have here a setup with two graphic cards and two displays.
The radeon 3650HD has my monitor connected to it via VGA
The radeon 3200HD has my TV connected via HDMI
I use KMS and the open driver and X works with two seperated screens so far
(hope xrandr support for multiple gpu comes fast) but I have a problem with
the framebuffer/KMS console.
The output from my console shows only on the TV not my monitor.
I can see the BIOS messages and use GRUB but then the monitor gets blank and
it says "no signal". I can read and see everything fine on my TV.
After X starts all is perfect.
It seems that the kernel or KMS are preferring the card with the HDMI TV over
the card with my vga TFT monitor.
Is there a boot option or something to tell the kernel that it should use the