I had the issue described above, and decided to give the nouveau driver
a try instead of the proprietary nvidia driver I had been using. I
cleared out all graphics card and monitor related sections from
xorg.conf file and replaced simply with
Section Device
Identifier nvidia card
Like virtually everyone posting here, I too have this problem. I have a
Macbook pro 3,1 with Karmic 9.10. When I wake the computer by opening
the lid, this occurs. If anyone with a macbook pro reads this, it seems
like I can keep the computer from going back to sleep by pressing the
power
