No option to suspend when power critically low; hibernate option greyed out

[Teo]

(no idea whether this is the right package)

In Power Settings, under "on battery" and "when power is critically low", the only available option is "Power Off". The "Hibernate" option is greyed out, and the option "Suspend" doesn't even exist, which is completely stupid.

Maybe hibernation is greyed out for the same reason why it's not available in the shutdown menu, that is, because it's unreliable as hell.
Besides the fact that it's about time to fix it, given we have already reached W in the alphabet of versions, anyway, since most of the time it works, the option should be available with a warning that it may fail to resume, rather than completely unavailable.

Regarding the "Suspend" option, it's simply stupid that it's not available. I know, suspend requires a minimum amount of power. But the solution to that is pretty obvious: if the selected choice is to suspend, then use a slightly higher threshold for triggering suspension. And if while suspended the power goes below the lower critical threshold for keeping suspension, then it should wake up and hibernate, or turn off (there should be an additional option for this).

I remember a few versions ago the option to suspend on low power did exist, and what happened was that the system started to suspend, immediately wake up, suspend again, and so on forever until the power was too low and it just hard-powered off. Now, I understand that was pathetic, but the new behavior is no solution. Also this proves that waking up when power reaches critical level while suspended is possible.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: powermgmt-base 1.31+nmu1
ProcVersionSignature: Ubuntu 3.19.0-43.49-generic 3.19.8-ckt10
Uname: Linux 3.19.0-43-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.17.2-0ubuntu1.8
Architecture: amd64
CurrentDesktop: Unity
Date: Thu Jan 7 23:31:53 2016
Dependencies:

InstallationDate: Installed on 2013-10-11 (818 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
PackageArchitecture: all
SourcePackage: powermgmt-base
UpgradeStatus: Upgraded to vivid on 2015-08-15 (145 days ago)