dear Lars,
On Mon, 23 Jan 2017, Lars Noodén wrote:
on my X220 running Debian Jessie with Linux kernel 4.7.0-0.bpo.1-amd64
from backports, suspend to memory succesfully works using:
  sudo pm-suspend
actually it worked also on the stock kernel version 3.*
the dmesg log sequence after a sleep and wakeup (pressing any keys)
 PM: Syncing filesystems ... done.
 PM: Preparing system for sleep (mem)
 PM: Suspending system (mem)
 PM: suspend of devices complete after 752.838 msecs
 PM: late suspend of devices complete after 16.180 msecs
 PM: noirq suspend of devices complete after 16.110 msecs
 PM: Saving platform NVS memory
 PM: Restoring platform NVS memory
 PM: noirq resume of devices complete after 17.645 msecs
 PM: early resume of devices complete after 0.391 msecs
 PM: resume of devices complete after 1184.715 msecs
 PM: Finishing wakeup.
the fact powerdown and shutdown don't work from the windowmanager is
known. I suspect the fork curated by Dima here may provide a solution
https://git.devuan.org/dimkr/xfce4-power-manager
ciao