[nouveau] desktop pc doesnt wake up after display going black, display connected over displayport

My desktop pc doesnt wake up anymore after the screen has gone black. I am suspecting that this has to do with the display being connected with DisplayPort.

I am running Ubuntu Budgie 18.04.2

I've replaced the DisplayPort cable with an HDMI cable now and the issue has resolved. So I can confirm that the issue is related to the display being connected with a DisplayPort cable.
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ProblemType: Bug
ApportVersion: 2.20.9-0ubuntu7.5
Architecture: amd64
BootLog: Error: [Errno 13] Keine Berechtigung: '/var/log/boot.log'
CompositorRunning: None
CurrentDesktop: Budgie:GNOME
DistUpgraded: Fresh install
DistroCodename: bionic
DistroRelease: Ubuntu 18.04
DistroVariant: ubuntu
DkmsStatus: virtualbox, 5.2.18, 4.18.0-15-generic, x86_64: installed
ExtraDebuggingInterest: Yes, including running git bisection searches
GraphicsCard:
 NVIDIA Corporation GP102 [GeForce GTX 1080 Ti] [10de:1b06] (rev a1) (prog-if 00 [VGA controller])
   Subsystem: ASUSTeK Computer Inc. GP102 [GeForce GTX 1080 Ti] [1043:85e4]
InstallationDate: Installed on 2019-02-19 (5 days ago)
InstallationMedia: Ubuntu-Budgie 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
LightdmDisplayLog:
 (EE) client bug: timer event3 debounce short: offset negative (-0ms)
 (EE) client bug: timer event3 debounce short: offset negative (-3ms)
 (EE) client bug: timer event3 debounce short: offset negative (-1ms)
MachineType: EVGA INTERNATIONAL CO.,LTD Default string
Package: xorg-server (not installed)
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.18.0-15-generic root=/dev/mapper/ubuntu--budgie--vg-root ro quiet splash vt.handoff=1
ProcVersionSignature: Ubuntu 4.18.0-15.16~18.04.1-generic 4.18.20
Tags: bionic ubuntu
Uname: Linux 4.18.0-15-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 12/29/2016
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 1.01
dmi.board.asset.tag: Default string
dmi.board.name: 134-KS-E279
dmi.board.vendor: EVGA INTERNATIONAL CO.,LTD
dmi.board.version: 1.0
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: EVGA INTERNATIONAL CO.,LTD
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1.01:bd12/29/2016:svnEVGAINTERNATIONALCO.,LTD:pnDefaultstring:pvrDefaultstring:rvnEVGAINTERNATIONALCO.,LTD:rn134-KS-E279:rvr1.0:cvnEVGAINTERNATIONALCO.,LTD:ct3:cvrDefaultstring:
dmi.product.family: Default string
dmi.product.name: Default string
dmi.product.sku: Default string
dmi.product.version: Default string
dmi.sys.vendor: EVGA INTERNATIONAL CO.,LTD
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.95-1~18.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 18.2.2-0ubuntu1~18.04.2
version.libgl1-mesa-glx: libgl1-mesa-glx 18.2.2-0ubuntu1~18.04.2
version.xserver-xorg-core: xserver-xorg-core N/A
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A