Computer Turns Off instead of Suspending/Sleeping

Firstly, thank you for submitting a very detailed and well set-out question.

I have a similar system set-up to you and have had almost the exact same situation occur, regarding suspend-resume for ages now.

I just found a fix which seems to work, detailed in a couple of other places including on this site. Suspend and resume problems seem to be rife in Ubuntu, for some reason.

The solution is simple:

• Edit the file /etc/default/grub (as root)

• Change the line with:

  GRUB_CMDLINE_LINUX=""
  

  to:

  GRUB_CMDLINE_LINUX="acpi_sleep=nonvs"
  

• run update-grub (as root)

As I say; this seems to work for me, so I hope it will work for others, too.

Suspend fails (reboot on resume) and no hibernate option