(In reply to comment #96)
> Not so fast fellas. Recently checked 3.11RC7 and DRM-Next (current). The
> result is the same: it still can't boot with my Radeon HD 2600 XT :(

Can you attach a copy of your vbios?

(as root)
(use lspci to get the bus id)
cd /sys/bus/pci/devices/<pci bus id>
echo 1 > rom
cat rom > /tmp/vbios.rom
echo 0 > rom

Also, can you get a copy of the dmesg output from the driver after it loads? 
Try booting into a non-X runlevel without loading radeon (either blacklist it,
or set radeon.modeset=0 on the kernel command line in grub) and then manually
load it.  E.g.,
modprobe -r radeon
modprobe radeon modeset=1 dpm=1

If possible, try and do it over ssh from a second machine so you can still
access it if you lose the display.