Toshiba Satellite L775 cannot suspend or hibernate 10.10 and 11.10

I have tried activating suspend and hibernate by various methods -- closing the lid, pressing the power button and selecting the suspend/hibernate button, or choosing suspend/hibernate from the menu, running pm-suspend or pm-hibernate from a terminal. I have tried all the various --quirks options. In every case, the screen goes to black with a non-blinking text cursor in the top-left corner. It does not sleep/power off the screen, wireless lan, fan or any other hardware that I am aware of. It will not wake from this state. I have to hold the power button to force it to power off and then reboot. When attempting to hibernate, it does sometimes restore the saved state after rebooting but not every time.