Comment 0 for bug 1929209

At times it is completely debilitating; at other times it does not happen for hours.
The physical connections are clean and solid.

There are other related behaviours reported in the past.
 I guess the attachments will show that I'm using Intel graphics hardware. The monitor is a very popular Samsung one.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xorg 1:7.7+19ubuntu14
ProcVersionSignature: Ubuntu 5.4.0-73.82-generic 5.4.106
Uname: Linux 5.4.0-73-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.17
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CasperMD5CheckResult: skip
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Thu May 20 16:56:04 2021
DistUpgraded: 2020-06-01 15:46:34,953 ERROR got error from PostInstallScript ./xorg_fix_proprietary.py (g-exec-error-quark: Failed to execute child process “./xorg_fix_proprietary.py” (No such file or directory) (8))
DistroCodename: focal
DistroVariant: ubuntu
DkmsStatus: virtualbox, 6.1.16, 5.4.0-73-generic, x86_64: installed
EcryptfsInUse: Yes
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation HD Graphics 5500 [8086:1616] (rev 09) (prog-if 00 [VGA controller])
   Subsystem: Lenovo HD Graphics 5500 [17aa:5036]
InstallationDate: Installed on 2019-01-24 (847 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.3)
MachineType: LENOVO 20BXCTO1WW
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-73-generic root=UUID=a6081f39-700f-4698-bda4-464e53d9d229 ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: Upgraded to focal on 2020-06-01 (353 days ago)
dmi.bios.date: 09/13/2017
dmi.bios.vendor: LENOVO
dmi.bios.version: JBET66WW (1.30 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20BXCTO1WW
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrJBET66WW(1.30):bd09/13/2017:svnLENOVO:pn20BXCTO1WW:pvrThinkPadT450s:rvnLENOVO:rn20BXCTO1WW:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad T450s
dmi.product.name: 20BXCTO1WW
dmi.product.sku: LENOVO_MT_20BX_BU_Think_FM_ThinkPad T450s
dmi.product.version: ThinkPad T450s
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.102-1ubuntu1~20.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 20.2.6-0ubuntu0.20.04.1
version.libgl1-mesa-glx: libgl1-mesa-glx 20.2.6-0ubuntu0.20.04.1
version.xserver-xorg-core: xserver-xorg-core 2:1.20.9-2ubuntu1.2~20.04.2
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:19.1.0-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20200226-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.16-1