Thank you. I found out the bug and solved it.
On Tue, 19 Feb, 2019, 09:20 Daniel van Vugt A purple screen while booting is normal. Can you please explain in
> different words what the problem is? Maybe with a photo or video?
>
> ** Package changed: xorg (Ubuntu) => ubuntu
>
> ** Changed in: ubunt
Public bug reported:
I have to enter nouveau.modeset=0 every time I login
ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu7
ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18
Uname: Linux 4.15.0-29-generic x86_64
NonfreeKernelModules: kpatch_livepatch_Ubuntu_4_15_0