Resolution to x220 failing to sleep

Question

For many months I was having a problem where my laptop would not sleep properly.  About 1 out of every 5 times that I slept the computer it would appear off with the screen blanked and keyboard unresponsive, but the fan would come on and the unit would get very hot.  This was very annoying because I'd have no other choice but to do a hard power reset on the device, and occasionally I'd put the laptop into my bag without noticing the problem.  Then I'd later find either a laptop completely drained of battery, or an extremely hot laptop in my bag.
This problem was occurring on both my wife's and my laptops (both x220 units), so it was not an isolated issue.  I suspect however this was caused in part because I had enabled UEFI boot on both systems.
I recently discovered through much trial and error that disabling the "ThinkPad PM Service" resolves the problem.  Unfortunately this seems to remove the ability to turn off the WiFi/Bluetooth/WWAN via Fn+F5, but I view that as an acceptable tradeoff for myself.
A diagnostic note in case anyone at Lenovo wants to look into this: Prior to discovering that disabling this service solved the problem, I attached a kernel debugger to see what the system state looked like during one of these sleep failures.  I was surprised to find that all of my processes which were running before the initiation of the sleep transition were still running, so I suspect the failure happens early in the sleep process shortly after the screen and keyboard are turned off. 
Also, the WiFi and Bluetooth lights retain their state, and the disk light still blinks on occasionally whenever some program initiates disk access.

Answer 1

Hello,
Maybe there is some information stored by the operating system that might be of use.
If you open an elevated Command Prompt (filename: CMD.EXE) and issue "powercfg -lastwake" and "powercfg -waketimer" commands, do they display any useful information about what the latest event was that woke the X220 up, and what events might cause the X220 to wake up?
Regards,
Aryeh Goretsky
I am a volunteer and neither a Lenovo nor a Microsoft employee. • Dexter is a good dog • Dexter je dobrý pes
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