Salve
Sto facendo un giro sul  sistema e forse ho trovato qualche informazione aggiuntiva per quanto riguarda il mancato funzionamento dei pulsanti di reboot e shutdown su fedora 19 kde.

Ho lanciato da menú kde sotto administration  Service Configuration
tra i vari servizi ho trovato:

       1. The rngd service is managed by systemd. It may be started then run in the background, or                 be  activated on demand, or run once for preparation or cleanup purposes.
                    This unit has failed: failed

       2. The systemd-reboot service is managed by systemd. It may be started then run in the                     background, or be activated on demand, or run once for preparation or cleanup purposes.
                    This unit is inactive.

     
3. The systemd-shutdownd service is managed by systemd. It may be started then run in the                 background, or be activated on demand, or run once for preparation or cleanup purposes.
                
This unit is inactive.

Non so quanto questi tre processi siano correlati tra loro ma forse qualcosa significano.

Giovanni