The screen is blinking at a random time

[Andrew G. Saushkin]

I've seen this error on Dell Latitude E7270 (with an internal video card) as well as Dell Precision 7540 (with NVidia card).

I've seen this error on Ubuntu 18.04 and now on 20.04

I've never reported it yet but I think the time has come.

In a random time (~ once a couple of weeks) I see a blinking screen. Today I've recorded a video on my phone to show you how it looks.

You can see it here: https://youtu.be/JiUu7Ydg6uM

This is bug finishes when I do logout from my desktop. Could you help me eliminate this error?

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: xorg 1:7.7+19ubuntu14
ProcVersionSignature: Ubuntu 5.4.0-28.32-generic 5.4.30
Uname: Linux 5.4.0-28-generic x86_64
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
CasperMD5CheckResult: skip
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
Date: Sat May 2 19:28:27 2020
DistUpgraded: Fresh install
DistroCodename: focal
DistroVariant: ubuntu
DkmsStatus:
 virtualbox, 6.1.6, 5.4.0-21-generic, x86_64: installed
 virtualbox, 6.1.6, 5.4.0-25-generic, x86_64: installed
 virtualbox, 6.1.6, 5.4.0-26-generic, x86_64: installed
 virtualbox, 6.1.6, 5.4.0-28-generic, x86_64: installed
ExtraDebuggingInterest: Yes, if not too technical
GraphicsCard:
 Intel Corporation Skylake GT2 [HD Graphics 520] [8086:1916] (rev 07) (prog-if 00 [VGA controller])
   Subsystem: Dell Skylake GT2 [HD Graphics 520] [1028:06db]
InstallationDate: Installed on 2020-04-09 (23 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Beta amd64 (20200402)
MachineType: Dell Inc. Latitude E7270
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-28-generic root=UUID=9427d12e-3c69-4eb4-aa23-52bfe8bd2641 ro quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 08/20/2018
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.20.3
dmi.board.name: 0T0V7J
dmi.board.vendor: Dell Inc.
dmi.board.version: A03
dmi.chassis.type: 9
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.20.3:bd08/20/2018:svnDellInc.:pnLatitudeE7270:pvr:rvnDellInc.:rn0T0V7J:rvrA03:cvnDellInc.:ct9:cvr:
dmi.product.family: Latitude
dmi.product.name: Latitude E7270
dmi.product.sku: 06DB
dmi.sys.vendor: Dell Inc.
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.101-2
version.libgl1-mesa-dri: libgl1-mesa-dri 20.0.4-2ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 20.0.4-2ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.20.8-2ubuntu2
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

[Andrew G. Saushkin (saushkin)]

It looks like visual bell goes crazy (but I'm not sure in that). And yes, I love visual bell and usually do enable visual bell instead of audio bell.

[Daniel van Vugt (vanvugt)]

Please try:

1. Disabling visual bell in Settings > Universal Access > Hearing > Visual Alerts = Off

2. Select 'Ubuntu on Wayland' from the login screen. Does that avoid the issue?

3. Next time the problem starts happening run:

   journalctl -b0 > journal.txt

   and then attach the resulting file here.

[Andrew G. Saushkin (saushkin)]

Thanks for your advice, I'll try to get the journal next time.

Unfortunately, this bug appearing not so often, and changing my desktop environment and be awaiting it around a couple of couple weeks is not very convenient for me. I'd suggest thinking about other ways of testing than the first two.

[Launchpad Janitor (janitor)]

[Expired for Ubuntu because there has been no activity for 60 days.]