Issues with power management

[solitone <solitone@mail.com>]

Hi,

as I told in thread "Monitor switched off after resume from hibernation", my 
MacBookPro 12,1 had problems with hibernation in stretch. If hibernation 
happened after the monitor had been switched off, the system would not turn 
the monitor on again after resume. Therefore I disabled hibernation.

With time, though, I noticed that even suspension doesn't work very well. 
Sometimes the laptop does not suspend, neither if I wait for the set 5 
minutes, nor if I close the lid. It basically remains active, cunsuming 
battery.

So today I tried to re-enable hibernation, and discovered that now it does not 
work at all. Perhaps it was a recent stretch update, but now hibernation can't 
be used at all. Previously it worked at least when the monitor was on. Now 
even when the monitor is on and I hibernate, when the system resumes I don't 
get a usable session. I just get an emtpy black screen with the white cursor 
on it, but nothing happens. I can't even switch to a virtual console with crtl
+alt+F<n>. 

What do you suggest to do to investigate this issue? A functional power 
management is a must on a portable computer.

Thanks!