Similar question to Monitor won't enter power save mode , however I only experience the problem under synergy. Screensaver settings work, but the monitors never go to sleep. When synergy is not running, monitors go to sleep at the interval set in Power Mgmt Preferences. I'm running synergy under my user account. Dell Desktop, Ubuntu 11.04, standard install video drivers (installing the proprietary drivers causes many errors.)
How can I troubleshoot this issue?