At ~25% after suspending my system, can't wake up.
Hard reboot (pressing the related button) is the only solution.

I tried alternative ways, but they all have the same problem.
Some of them, which used to work with KDE 4, are useless nowadays.

If someone knows a proper and bug-free way of suspension (that actually works in KDE 5), I'll be glad to know!

PS. Suspending to disk, is flawlessly, but it takes way much time for waking up, so this is not an accepted alternative for me.