09-06-2015 08:20 PM
I've been having this issue sporadically, where my W520 will fail to enter suspend. The screen goes dark, backlight goes off, but the fan continues to spin and the status lights remain lit. I've tried leaving it for several minutes.
After running `powercfg -energy` twice, once while docked and once while on disconnected and battery power, it appears to have narrowed down the culprit to the USB hub(s) in the docking station.
There don't seem to be any special drivers available or required for this thing. What else can I try?