May not be in your case, but the bios also has settings for blanking the screen, which could conceivably activate without Linux help (I've seen this happen for my disk at least after I had to restore bios settings and left those on).
Volker -- Volker Kuhlmann is possibly list0570 with the domain in header http://volker.dnsalias.net/ Please do not CC list postings to me.
