No it doesn't work. with old kernel which I used module radeon cannot be found. With new kernel mkinitrd has found radeon module, but '--preload radeon' gave strange result and that is blinking ttys and no X.
Then I ran it without --preload and now I have same situation as before with the difference that if I switch to tty before gdm login screen system doesn't freeze, and if I 'kill' gdm-binary everything is back to normal!
I have tried adding killall gdm-binary in rc.local but that doesn't work...