Suspend problem on Sony Vaio
 

I've just installed Mandrake 9.2 on a sony vaio z505ls, and it seems to be worky pretty well. I have one problem, however: when I suspend using the "apm -s" command, it works pretty well, except for the fact that if i leave it suspended for more than a couple minutes, when I try to bring it back online, it shows the "display locked" screen for about half a second, and then the screen goes blank and shows a weird psychedelic type effect moving across the screen. after that, the computer doesn't respond to input at all, and i have to reboot it. Am I doing something incredibly wrong?

Any help would be greatly appreciated.
Thanks,
Stu