This behaviour happens only with desktop effects enabled. When I logout from the desktop to return at the KDM greeter I see only a black screen, but I can insert the password of my user and login into the desktop Reproducible: Always Steps to Reproduce: 1.login with an user 2.be sure that the Desktop effects are enabled 3.logout from KDE and return to the KDM Actual Results: I see a black screen Expected Results: The KDM greeter I use only machines with Radeon cards and open source drivers, I am unable to define if this detail is relevant
Latest version of Xorg Radeon drivers (7.1.x) fix the problem