Comment 74 for bug 559163

The two things that absolutely worked for me on the Dell Latitude D600 were :

1) Setting the primary password in Bios (I'm running version A16)
2) Modifying the GRUB_CMDLINE_LINUX setting in /etc/default/grub as follows:
GRUB_CMDLINE_LINUX="radeon.modeset=0"

Nothing else worked.

Since I'd prefer not to have a primary password, (it's a useless feature), I went with the second solution.