"Hibernate" missing in 16.04 PPC

What is the reason that there is no “Hibernate” (i.e. Sleep Mode, Suspend-to-disk) offered in 16.04 PPC?
When booting from the Live-CD “Hibernate” was offered as an option after clicking on “Shut down”.
After installation it is not available.

Did some additional research and found an article in the official Ubuntu documentation:
“How do I hibernate my computer?”
https://help.ubuntu.com/stable/ubuntu-help/power-hibernate.html

According to this article hibernate can be tested with the command:
sudo pm-hibernate
This causes a total freeze of my system; even if I increase the size of the swap-partition to twice the size of RAM.

In the Ubuntu documentation it says “Unfortunately, hibernate doesn’t work in many cases …”, but as the only cause for that a swap partition being to small is mentioned.
I am surprised to hear that. On 3 of the boxes I use, hibernate works perfectly and I had never ever ans issues with it:

  • Mac G5 PPC, with OS X 10.5.8 (prior to the parallel installation of 16.04)
  • HP 5103, with elementary OS “Freya” (based on Ubuntu 14.04)
  • AMD x86_64 desktop, with elementary OS “Luna” (based on Ubuntu 12.04)
    Especially the Mac G5 wakes up from hibernate and is fully operationall within seconds.

Seems to be a bug. Hibernate is a key feature for me. Is there a way to make this work?