Comment # 14 on bug 1219020 from Dmitry Markov

(In reply to Antonio Feijoo from comment #13)
> Sorry, I should've asked to add `systemd.log_level=debug` in the kernel
> command line to be able to see what's happening. But, I was able to
> reproduce your issue locally, and the logs match what you wrote in comment
> #1:
> 
> > [   82.172170] localhost systemd-logind[1065]: Got message type=method_call sender=:1.21 destination=org.freedesktop.login1 path=/org/freedesktop/login1 interface=org.freedesktop.login1.Manager member=SetWallMessage  cookie=2 reply_cookie=0 signature=sb error-name=n/a error-message=n/a
> > [   82.172170] localhost systemd-journald[792]: Forwarding to syslog missed 464 messages.
> > [   82.172383] localhost systemd-logind[1065]: Sent message type=method_return sender=n/a destination=:1.21 path=n/a interface=n/a member=n/a cookie=58 reply_cookie=2 signature=n/a error-name=n/a error-message=n/a
> > [   82.172406] localhost systemd[1]: systemd-logind.service: Got notification message from PID 1065 (WATCHDOG=1)
> > [   82.172522] localhost systemd-logind[1065]: Got message type=method_call sender=:1.21 destination=org.freedesktop.login1 path=/org/freedesktop/login1 interface=org.freedesktop.login1.Manager member=HibernateWithFlags  cookie=3 reply_cookie=0 signature=t error-name=n/a error-message=n/a
> > [   82.172637] localhost systemd-logind[1065]: Failed to open configuration file '/etc/systemd/sleep.conf': No such file or directory
> > [   82.172660] localhost systemd-logind[1065]: Sleep mode "disk" is supported by the kernel.
> > [   82.172694] localhost systemd-logind[1065]: Disk sleep mode "shutdown" is supported by the kernel.
> > [   82.172720] localhost systemd-logind[1065]: /dev/dm-1: is a candidate device.
> > [   82.172737] localhost systemd-logind[1065]: No swap partitions or files matching resume config were found in /proc/swaps.
> > [   82.172760] localhost systemd-logind[1065]: Sent message type=error sender=n/a destination=:1.21 path=n/a interface=n/a member=n/a cookie=59 reply_cookie=3 signature=s error-name=org.freedesktop.login1.SleepVerbNotSupported error-message=Not enough swap space for hibernation
> > [   82.172778] localhost systemd-logind[1065]: Failed to process message type=method_call sender=:1.21 destination=org.freedesktop.login1 path=/org/freedesktop/login1 interface=org.freedesktop.login1.Manager member=HibernateWithFlags cookie=3 reply_cookie=0 signature=t error-name=n/a error-message=n/a: Not enough swap space for hibernation
> 
> With the following actions I managed to make it work:
> - Set `resume=/dev/mapper/cr_swap` on the kernel command line.
> - Remove `add_device+=" UUID=... "` from /etc/dracut.conf.d/99-resume.conf
> - In /etc/crypttab, append the following two options to the cr_swap entry
> (4th column): x-initrd.attach,force
> - Run `dracut -f`
> - Reboot and try again `systemctl hibernate`.
> 
> If it does not work in your system, add `systemd.log_level=debug` and attach
> the output of `journalctl -b -o short-monotonic`. Thanks.

I'm back with good news
As I understand it, adding `x-initrd.attach` to crypttab helped.
Now hibernation works as it should. it might make sense to note this in the
documentation from the first comment.
wi-fi does not work when waking up, but this is not the topic of this
bugreport.

thanks for help!