This may be a bug - I am testing Ubuntu 13.04 64bit. I have a HP Envy Extreme XT 13.3
When I suspend and resume, I have a blank screen. However I can still enter my password and then wait a few moments and press either of the screen brightness buttons and the screen wakes up.
More information - this PC uses an Intel graphics HD 4000 - Graphics drive is Intel Ivybridge Mobile