Comment 16 for bug 869119

 - does hitting 'esc' once instead of Alt+F6/Alt+F7 fix the issue?
Yes - I get a text-only password prompt

 - does hiting 'esc' *twice* fix the issue?
Yes - I see the graphical password prompt (= GPP)

 - does hitting Alt+F7 *without* hitting Alt+F6 fix the issue?
No - screen switches to powersave (no backlight) but accepts password typed blindly

 - what do you see if you boot without the 'quiet' option (but still with the 'splash' option)?
Depends on how, I remove the quiet:
a) If I trigger the grub boot menu, I always correctly get the GPP invariant of quiet or not quiet
b) Removing quiet from /etc/default/grub and running update-grub still leaves me with the screen in powersave

This machine is a notebook, originally installed with either oneric or natty alternate CD and updated up to quantal without reformating the hard-disk since.