differences between suspend methods

[Peter F. Patel-Schneider]

Hi:

Iam trying to diagnose why my laptop behaves differently when using different 
suspend methods. I'm running Fedora 20 on a Lenovo Yoga 2 Pro.

When I suspend from the "Log Out" menu item, my laptop stays suspended.  
However, when I suspend by closing the laptop's lid, the laptop often 
immediately wakes up.

I suspect that the lid close method is not correctly preparing the laptopfor 
suspension, and that some device is initiating the wakeup. However, I don't 
know where to look to find out who is doing what, and how.

Does anyone have pointers to gooddescriptions of howsuspend is done in XFCE 
and Fedora?

peter