In a previous thread I mentioned the strange issue on Plasma DE that prevented me to start
NetworkManager and use the power options as user. So I tried to see whether my consolekit
session was active or not, but % ck-list-sessions gave me no output at all! So I thought
that a .xsession file was needed and edited it adding "exec ck-launch-session
startplasma-x11". On reboot I was able to connect to my wireless network as user, and
all the power options were back and working! Of course it's only a workaround, because
I really don't know why sddm could not get consolekit to start normally, but at least
my DE is usable now. Hope this helps.