[nvidia] DisplayPort over USB-C stopped working.

Ubuntu cannot use the usb-c as monitor connection. It stopped working last week. (December 2021)
Unfortunately I don't know which update broke the support, or which package is involved.

The USB-c port is provided by the nvidia graphics card. (tu116)
This feature is not supported by nouveau driver, only with the closed source nvidia driver.

I hope this is useful.
Please help me to provide further and better information.

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: xorg 1:7.7+22ubuntu2
ProcVersionSignature: Ubuntu 5.13.0-23.23-generic 5.13.19
Uname: Linux 5.13.0-23-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
.proc.driver.nvidia.capabilities.gpu0: Error: path was not a regular file.
.proc.driver.nvidia.capabilities.mig: Error: path was not a regular file.
.proc.driver.nvidia.gpus.0000.01.00.0: Error: path was not a regular file.
.proc.driver.nvidia.registry: Binary: ""
.proc.driver.nvidia.suspend: suspend hibernate resume
.proc.driver.nvidia.suspend_depth: default modeset uvm
.proc.driver.nvidia.version:
 NVRM version: NVIDIA UNIX x86_64 Kernel Module 470.86 Tue Oct 26 21:55:45 UTC 2021
 GCC version: gcc version 11.2.0 (Ubuntu 11.2.0-7ubuntu2)
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
BootLog: Error: [Errno 13] Keine Berechtigung: '/var/log/boot.log'
CasperMD5CheckResult: unknown
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Sun Dec 12 14:41:46 2021
DistUpgraded: 2021-10-19 09:59:35,486 DEBUG Running PostInstallScript: '/usr/lib/ubuntu-advantage/upgrade_lts_contract.py'
DistroCodename: impish
DistroVariant: ubuntu
DkmsStatus: nvidia, 470.86, 5.13.0-23-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 NVIDIA Corporation TU116M [GeForce GTX 1660 Ti Mobile] [10de:2191] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. TU116M [GeForce GTX 1660 Ti Mobile] [1043:171f]
 Advanced Micro Devices, Inc. [AMD/ATI] Renoir [1002:1636] (rev c6) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. Renoir [1043:171f]
InstallationDate: Installed on 2020-10-21 (417 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Beta amd64 (20200930)
MachineType: ASUSTeK COMPUTER INC. ROG Zephyrus G15 GA502IU_GA502IU
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.13.0-23-generic root=UUID=77b295d5-6e8e-48a4-9a81-fc5e22648a4f ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: Upgraded to impish on 2021-10-19 (54 days ago)
dmi.bios.date: 12/30/2020
dmi.bios.release: 5.16
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: GA502IU.221
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: GA502IU
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.ec.firmware.release: 3.13
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrGA502IU.221:bd12/30/2020:br5.16:efr3.13:svnASUSTeKCOMPUTERINC.:pnROGZephyrusG15GA502IU_GA502IU:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnGA502IU:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:sku:
dmi.product.family: ROG Zephyrus G15
dmi.product.name: ROG Zephyrus G15 GA502IU_GA502IU
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.107-8ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 21.2.2-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 21.2.2-1ubuntu1
version.nvidia-graphics-drivers: nvidia-graphics-drivers-* N/A
version.xserver-xorg-core: xserver-xorg-core 2:1.20.13-1ubuntu1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-2build1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200714-1ubuntu2
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.17-1build1