User reported trying to use kdm with lxde today, and couldn't powerdown his box due to /etc/pam.d/kdm missing: -session optional pam_ck_connector.so
Actually it was with XFCE (not lxde), which uses ConsoleKit to ask PolicyKit for gaining permissions.
kde-settings-4.8-18.fc17 has been submitted as an update for Fedora 17. https://admin.fedoraproject.org/updates/kde-settings-4.8-18.fc17
In the long run, Xfce needs to be patched to use systemd instead, as I did for kde-workspace (though kde-workspace also supports shutdown/restart through KDM, which is currently preferred to using systemd when KDM is used). Changing this for shutdown/restart is relatively straightforward. User switching is more complicated and in fact the user switching code in my kde-workspace patch might not be working. (We were unable to test user switching in the F17 release phase because it was also not working in GNOME due to some systemd or GDM issue.) But the shutdown/restart part definitely works. This is the patch we're using for kde-workspace: http://pkgs.fedoraproject.org/cgit/kde-workspace.git/tree/kde-workspace-4.8.0-systemd-shutdown.patch Do we already have a bug filed against Xfce for that?
Package kde-settings-4.8-18.fc17: * should fix your issue, * was pushed to the Fedora 17 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing kde-settings-4.8-18.fc17' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2012-11702/kde-settings-4.8-18.fc17 then log in and leave karma (feedback).
The right command is : # su -c 'yum update --enablerepo=updates-testing kde-settings-kdm-4.8-18.fc17.noarch' it solves the problem.
kde-settings-4.8-18.fc17 has been pushed to the Fedora 17 stable repository. If problems still persist, please make note of it in this bug report.