How do I get “systemctl hibernate” followed by power-on to resume login sessions (PureOS latest, Librem 14)

Software PureOS
1

I used a PureOS USB drive that I ordered from Purism to install PureOS latest on a 2 TB SSD drive that I installed in my new Librem 14.
While installing, I selected “swap (with hibernate)”.
“free -h” reports the swap partition size is 68Gi.
When I run “systemctl hibernate” the system appears to hibernate.
The last 5 log messages before shutdown are:

systemd[1]: Reached target Sleep.
systemd[1]: Starting Hibernate …
kernel: PM: Image not found (code -22)
wpa_supplicant[PID]: nl80211: deinit ifname=wls6 disabled_11b_rates=0
systemd-sleep[PID]: Suspending system…

When I power the computer back on, there seems to be no sign whatsoever of any attempt to resume the machine state before the hibernate.
The computer behaves as if I had shut it down rather than hibernated it.
There do not appear to be any relevant log messages after the power-on.

I have failed to understand my problem from the other topics on this forum that mention hibernation.

What do I need to do to get hibernation to work?
Why is it not sufficient that I selected the “swap (with hibernate)” option while installing?

Thanks for any help you can provide! Long live free software!

2

do you use pureboot by accident?
cat /proc/cmdline please.
check if there is no noresume flag in kernel cmdline.

3

no, i did not order pureboot.

/proc/cmdline:

BOOT_IMAGE=/vmlinuz-5.10.0-8-amd64 root=UUID=4c1bc3fe-185e-4b95-b9f6-a42360828e19 ro quiet splash resume=/dev/mapper/luks-e375b64a-1b16-432f-8a54-ea42f1bec8e3 vt.handoff=7

thanks for any help you can give!

4

as far as i know hibernation don’t play well with encrypted swap. but i am unsure about that. last time i play with this was ages ago.

well you will have to hack initrd, to make it work, add special hook responsible for decrypting swap on resume
https://wiki.archlinux.org/title/Dm-crypt/Swap_encryption <- some examples done on arch linux - i am using archlinux docs as they have most detailed one.
that can be handy
https://gist.github.com/HacKanCuBa/b8565369de9620ba1eb24b75ee836857