how to make linux prefer sudo pm-hibernate over systemctl hibernate as default?
I faced the same problem on Ubuntu 18.10. You need to edit the hibernation service :
sudo systemctl edit systemd-hibernate.service
then paste this:
[Service]
ExecStart=
ExecStartPre=-/bin/run-parts -v -a pre /usr/lib/systemd/system-sleep
ExecStart=/usr/sbin/s2disk
ExecStartPost=-/bin/run-parts -v --reverse -a post /usr/lib/systemd/system-sleep
Save, then:
sudo systemctl daemon-reload
Run sudo systemctl hibernate it should work now.