'm running Debian Testing (Stretch) with a KDE desktop. I have plasma-workspace 4:5.4.1-1 and sddm 0.12.0-4 installed. My problem is that I cannot restart or shutdown from KDE in a normal way: going to the "Leave" menu from the Application launcher and selecting either Restart or Shut down from the System section of Leave.

Click on either one takes me to the SDDM login screen. If I try to restart or shut down from there I get a counter which counts down to 0 and then goes into negative numbers and would continue forever unless I cancel the operation.

I have two ways to shut down or restart KDE (besides simply turning off the computer:
a. I can log into Gnome Flashback Metacity from the login window and either restart or shut down from there. Interestingly, I get a dialogue box to enter the root password. I cannot do this with my normal user privileges as I did in the past.
b. I can Ctl-Alt-F1 to a tty, log in as root and give either the reboot or halt command.

So the problem seems to be that KDE now requires root privileges to either restart or shut down but does not provide the means to get these privileges.


Reproducible: Always

Steps to Reproduce:
1. Restart KDE as described above.
2. Click on either Restart or Shut down from the Leave menu.
3.

Actual Results:  
This takes me to the Login page. Clicking on the Restart or Shut Down symbols counts down to 0 seconds and then goes into negative numbers.