SDDM shows a black screen when nvidia-driver-470 is updated to 470.74

[Karsten]

This bug is encountered on a computer with:

Kubuntu 21.10
MSI Gaming X Trio 3060 Ti

The following repo is used:

ppa: kubuntu-backports

GPU driver:

Nvidia driver metapackage from nvidia-driver-470(proprietary, tested)

What I expected: SDDM working just fine, showing every elements
What happened: SDDM is showing a black screen on login, logout, lockscreen. BUT logging in works.
What I did: Updating nvidia-driver-470 from 470.63 to 470.74
What I tried to do to fix: dpkg-reconfigure sddm

I suspect something is conflicting SDDM with the 470.74 driver. Downgrading to 470.63 will fix this problem.

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: nvidia-driver-470 470.74-0ubuntu1
ProcVersionSignature: Ubuntu 5.13.0-20.20-generic 5.13.14
Uname: Linux 5.13.0-20-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu70
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: KDE
Date: Thu Oct 21 20:19:55 2021
InstallationDate: Installed on 2021-08-24 (58 days ago)
InstallationMedia: Kubuntu 21.04 "Hirsute Hippo" - Release amd64 (20210420)
ProcEnviron:
 LANGUAGE=en_HK:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_HK.UTF-8
 SHELL=/bin/bash
SourcePackage: nvidia-graphics-drivers-470
UpgradeStatus: Upgraded to impish on 2021-10-21 (0 days ago)

[Karsten (karst124)]

Disabling G-SYNC on G-SYNC compatible monitor fixed this issue.

Refer to: https://dev.getsol.us/R2210:8889aa630ca826262f1c3d28f4e208e6f314294b