I have reinstalled the whole system with kde plasma desktop, nvidia-driver and when I do startx the screen become black and does not show anythink. I can see the nvidia logo for a second and after that all become black. The system is running because if a switch to a console, the screen ramain black, but i can put command. Initially, with nouveau driver the system had run well Reproducible: Always
*** This bug has been marked as a duplicate of bug 571632 ***
It seems not to be the same issue, because I have tried to downgrade to nvidia drivers version 358.16 but the problem still remain. In the log files I don't see any crash or error. The screen simply remain black
Actually I use nvidia-drivers-361.28
SOLVED. I only added user sddm to video group and the system is running well Thanks