Unlike KDM, GDM outsources services such as shutdown, restart and parts of session switching to a lower-level component. Until and including Fedora 16, that component was ConsoleKit. Starting from Fedora 17, it is systemd. Support for systemd in kde-workspace was developed in Fedora and needs testing.
You need to have the gdm package installed - yum install gdm.
How to test
- If your current display manager is KDM, switch to use GDM:
- Switch to a virtual terminal using Ctrl+Fkeys
- Login as root, and stop the GDM service: service gdm stop
- Start kdm: service kdm start. KDM login screen should now appear.
- If autologin to GNOME was enabled, start by logging out of GNOME.
- Log into KDE Plasma Desktop. (GDM allows selecting the session type after you enter the user name, on the password prompt screen.)
- Try shutting down, rebooting or switching users from the KDE Plasma Desktop Workspace.
- Shutdown and restart should work.
- User switching should also work.