My HP 8540w has spotty 'resume' (from memory).
That is, 80% of the time, it'd come back, the rest it'll just show a blank screen. In the linux world, this is sort of expected for a laptop. This is how bad things are.

But I suspect it's an X crash. If I could at least get to a terminal, I could restart X.

What I've found is that I have no virtual terminals (!).
That is, ctrl alt F1-F7 does nothing!

This is very serious. I'm running KDE and the proprietary nvidia drivers. But I don't think that matters much.

Where would you start debugging?