Nvidia, SDDM, Display port and DVI

[Hans Henrik Jakobsen]

Here is my problem:

When I upgrade from Kubuntu 14.04 or Install Kubuntu 16.04 I have a black screen after the Kubuntu logo disappear during boot.

I have found so that it's a problem with having a DVI and Diaplay port monitor connected at the same time and using SDDM with Nvidia (both a GTX970 and 650ti have been tested). I have 4 monitor connected and it's not a problem with 14.04.

If I change from SDDM to LightDM then I get a login screen and I can login but the plasma session never start and I get this error in LightDM log:

[+46.78s] DEBUG: Seat seat0: Failed to find session configuration kde-plasma
[+46.78s] DEBUG: Seat seat0: Can't find session 'kde-plasma'

The funny part is if I don't reboot and go back to SDDM (dpkg-reconfigure) and restart the SDDM service I get a login screen, can login and get a plasma session.

The reason I don't believe my problem is related to X or the Nvidia driver is there is no error in the X nor the Nvidia log. The SDDM log is empty (zero bytes).

My problem with SDDM is it has problems initialize when both an DVI and a display port monitor is connected at the same time. If I disconnect either of them will SDDM work just fine.

I have tried with the "kubuntu" drivers, xorg-edgers drivers, nvidias own drivers and Cuda 7/8 (because of my graphics needs I need Cuda installed).

Anybody know how I can fix SDDM black screen or get LightDM to start plasma5?

[Hans Henrik Jakobsen (sinhenrik)]

Issue resolved it's self.
One Of my monitors broke down and I replaced the monitor with the Display Port.
The monitor is a Samsung U28D590D giving the problem is very early production.
Every time I connect this monitor and a DVI/HDMI monitor SDDM will not show the login screen.

[Simon Quigley (tsimonq2)]

Thank you for taking the time to report this bug and helping to make Kubuntu better. We are sorry that we do not always have the capacity to look at all reported bugs in a timely manner. There have been many changes in Kubuntu since that time you reported the bug and your problem may have been fixed with some of the updates. It would help us a lot if you could test it on a currently supported Kubuntu version. If you test it and it is still an issue, kindly upload the updated logs by running only once:
apport-collect 1641382

and any other logs that are relevant for this particular issue.

[Launchpad Janitor (janitor)]

[Expired for Kubuntu PPA because there has been no activity for 60 days.]