Comment 9 for bug 994105

I had the same problem: in 11.10, I was using an MCE remote control to wake the machine from suspend, having added the line "echo USB0 >> /proc/acpi/wakeup" to /etc/rc.local. After upgrading to 12.04, this line no longer had any effect, although I could still manually enter "sudo sh -c 'echo USB0 >> /proc/acpi/wakeup'" at the terminal to activate wake from suspend.

For anyone else with this issue, the thread at http://ubuntuforums.org/showthread.php?t=1968487 gave a fix which worked for me; it involves editing the file /etc/udev/rules.d/90-keyboardwakeup.rules.