Comment 0 for bug 1577041

After upgrading kubuntu from 15.10 to 16.04, my system no longer boots to the login screen. There is a lot of flickering and the kubuntu logo is sometimes shown, sometimes a black screen. I am able to login to a terminal tty and see the following line from dmesg:

sddm[3968]: segfault at 0 ip 00007f31f9a776c3 sp 00007fff6b1c9b60 error 4 in libQt5Core.so.5.5.1

I discovered that removing the nvidia driver package resolves the situation and makes it possible to login to the desktop again. However, that makes it impossible for me to use my Nvidia graphics device.

I have a laptop with an Intel skylake CPU (i5-6200U) and an Nvidia Geforce 940M graphics card.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: kubuntu-desktop 1.338
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
CurrentDesktop: KDE
Date: Sat Apr 30 20:59:40 2016
InstallationDate: Installed on 2016-02-03 (87 days ago)
InstallationMedia: Error: [Errno 13] Permission denied: '/var/log/installer/media-info'
SourcePackage: kubuntu-meta
UpgradeStatus: No upgrade log present (probably fresh install)