nce upon a time my Ubuntu test machine (with an Nvidia GeForce4 MX Integrated GPU) wouldn’t resume from suspend or hibernate. It would turn back on, but only display a blank or purple screen, depending on its mood, and require a hard reboot (holding down the power button for 5 seconds). Turns out there is a simple fix. Of course I tried all the complicated fixes before finding this one, but let my experience save you time. Add this to your /etc/X11/xorg.conf file in the “Device” section:
Option "NvAGP" "1"
This does not work for Ubuntu Natty 11.04, which ignores the xorg.conf file.
To take the edge off of my hard fought victory, I found that when I did successfully resume, the system prompted me for a password to get back in. This wasn’t expected behavior, as I have auto-login turned on, and screensaver password turned off. I discovered that this is indeed an unresolved bug, stretching way back to old versions of Ubuntu. No matter what settings you change in various conf files or gnome-editor, the system ignores them. The only thing you can do is simply disable the lock screen. (I know, for some people that won’t be a good option, but I’m more concerned with convenience than security for this machine.). In the terminal:
gconf-editor
Go to desktop/gnome/lockdown, and check disable_lock_screen.
Sources: NvidiaLaptopBinaryDriverSuspend, Disabling the suspend and hibernate locks via gconf-editor doesn’t do anything (from Intrepid to lucid included)
UPDATE: To also make sure the system will resume by pressing any key, ensure that feature is enable in the BIOS, and then add this to /etc/rc.local before exit 0 and restart:
echo "USB0" > /proc/acpi/wakeup
Source: Ubuntu Suspend / Wake