How can I explore what is causing my laptop to not come out of suspend properly when the lid is opened?

[Michael Shiloh]

For years I had been hibernating my laptop (Lenova T60 and now T61) 
instead of shutting down, and of course opening the lid did nothing 
until I pressed the power button. Besides the long amount of time it 
would take to come out of hibernation, this SEEMED to work fine, 
although sometimes I was presented with a login screen instead of an 
unlock screen, suggesting that I was booting up fresh rather than simply 
coming out of hibernation.

Recently I've learned that suspend is quite reliable and of course much 
faster. I suspend either automatically on lid closure, or manually, and 
come out of suspend automatically when I open the lid.

Occasionally, coming out of suspend fails. The power indicator light is 
on, as well as bluetooth and wifi. Wifi is even blinking occasionally, 
but I don't know what this means. The disc activity light is off.

The only keys that are recognized are the "NmLk" and the little lamp 
that lights up the keyboard. I suspect these are handled by a 
microcontroller running the keyboard and not the main processor.

Every other key and key combination I can think of is ignored, e.g. 
"Ctrl" "Alt" F1 etc. to get a console login.

I have tried closing and reopening the lid, applying and removing 
external power, and pressing every single key, along with every 
combination of "Shift" "Ctrl" and "Alt", as well as the blue "Fn" 
button. Other than the numlock and keyboard lamp, nothing has any effect.

I have tried both hibernating automatically on lid closure, and 
hibernating manually prior to lid closure. The problem seems worse when 
I hibernate automatically, but this is not a terribly scientific conclusion.

I realize now that I may have been seeing the same problem when coming 
out of hibernation.

I recognize that the problem may not be been caused by a problem 
starting up, but rather, due to some error while hibernating or suspending.

What can I do to debug this? Any suggestions, comments, and ideas would 
be appreciated

Michael