KDE Plasma Wayland session does not detect external monitor

[JPT]

On my Thinkpad W530 the external monitor attached to the dock only is active until login. After login it disappears from available monitors, loses signal and the internal monitor is active only.

Workaround: Uses X11 session.
So I don't need a solution. But maybe the info gathered helps you fixing bugs.

I recently tried these
GRUB_CMDLINE_LINUX="acpi_osi='Windows 2012'"
GRUB_CMDLINE_LINUX="acpi_osi=! \"acpi_osi=Windows 2012\""
because I' having problems with ACPI and detection of DVD-Drive.

but I disabled them after my screen did not work any more after upgrade. (yeah I did the upgrade to impish rather late)
So I think this is not related.

My logfiles might be spammed with DVD read errors because I am currently reading bad DVDs. Just ignore them.

Release: 21.10

Wayland related version numbers. Package with wayland in name and not listed are not installed.

kwayland-data: 4:5.86.0-0ubuntu1
kwayland-integration: 4:5.22.5-0ubuntu1
kwin-wayland: 4:5.22.5-0ubuntu1
kwin-wayland-backend-drm: 4:5.22.5-0ubuntu1
libkf5waylandclient5: 4:5.86.0-0ubuntu1
libkf5waylandserver5: 4:5.86.0-0ubuntu1
libkwaylandserver5: 5.22.5-0ubuntu1
libqt5waylandclient5: 5.15.2-4
libqt5waylandcompositor5: 5.15.2-4
libva-wayland2: 2.12.0-2
libwayland-client0: 1.19.0-2build1
libwayland-cursor0: 1.19.0-2build1
libwayland-egl1: 1.19.0-2build1
libwayland-server0: 1.19.0-2build1
plasma-workspace-wayland: 4:5.22.5-0ubuntu1
qtwayland5: 5.15.2-4
xwayland: 2:21.1.2-0ubuntu1.1

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: plasma-workspace-wayland 4:5.22.5-0ubuntu1
ProcVersionSignature: Ubuntu 5.13.0-30.33-generic 5.13.19
Uname: Linux 5.13.0-30-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Tue Mar 8 14:03:05 2022
SourcePackage: plasma-workspace
UpgradeStatus: Upgraded to impish on 2022-02-27 (9 days ago)

[Daniel van Vugt (vanvugt)]

I'm guessing the dock uses DisplayLink, in which case the compositor needs to have implemented special support for that (like mutter/gnome-shell already has). To confirm this theory, please tell us the model of dock as well as running:

  lsmod > lsmod.txt
  journalctl -b0 > journal.txt

and attach the resulting text files here.

[JPT (j-p-t)]

Dock type 4338
logfiles attached. they are from an x11 session.
should I create some from wayland session too?

I removed DVD errors (from reading bad DVD) from the logfile because else it would have 20 MB.

Any way to find out about displaylink?

[Daniel van Vugt (vanvugt)]

OK forget what I said about DisplayLink because there's no mention of 'evdi' in those files.

The main suspect now is the nvidia-390 driver. Any monitor port connected to the Nvidia GPU will only work in Wayland sessions if your compositor supports EGLStreams, like we already do in gnome-shell. So I think this is probably a Plasma/KDE bug relating to EGLStreams support.

In this situation using a Xorg session is indeed one solution. But you should contact KDE developers for a more detailed analysis in case I've missed something.

[Scarlett Gately Moore (scarlettmoore)]

This bug is very old, if it is still an issue please update the bug with information from a supported release.

[JPT (j-p-t)]

Just close the bug please.
I gave this machine to some children from Ukraine. they are using windows.