I had the problem that my brand new Lenovo X200 wouldn’t wake up from suspending under Ubuntu 8.10. My laptop would go to sleep just fine and display the green moon but when waking up again the computer would freeze for a minute or so before the computer restarted by it self. I found this bug report that is identical to my problem:
The solution, for me at least, was to change the boot parameters to include the line acpi_sleep=s3_bios. This is most easily done by editing the file called /boot/grub/menu.lst in the section starting with #kopt. Change the line that is similar to this:
# kopt=root=UUID=abef640b-ba25-46a3-94d1-5ed838f85f56 ro
so it contains acpi_sleep=s3_bios:
# kopt=root=UUID=abef640b-ba25-46a3-94d1-5ed838f85f56 ro acpi_sleep=s3_bios
After this the command update-grub should be run:
Once the computer has been restarted suspend should work.