Comment 1 for bug 1325309

I'm afraid logind does require cgroups to be available. The init script reflects that, as without the cgroup mount logind wouldn't work. You already noticed the failure to suspend etc., but I'm quite surprised that you get a desktop session at all. I expect that dynamic ACLs to devices (sound, USB, etc.) are also not working.

So I recommend enabling cgroups in your custom kernels. This should hardly have any power usage effect?