Bug 437734

Summary:	External displays doesn't show picture wia dock station. After Kubuntu release upgrade
Product:	[Plasma] KScreen	Reporter:	Włodzimierz Ciesielski <wlodzimierz.ciesielski>
Component:	common	Assignee:	kscreen-bugs-null <kscreen-bugs-null>
Status:	RESOLVED MOVED
Severity:	normal	CC:	cuchac, nate, plasma-bugs-null, xaver.hugl
Priority:	NOR	Keywords:	multiscreen
Version First Reported In:	5.21.4
Target Milestone:	---
Platform:	Kubuntu
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:	5.21
Sentry Crash Report:

Description Włodzimierz Ciesielski 2021-05-27 11:52:40 UTC

SUMMARY
At Kubuntu 20.10 everithing works fine. After update to Kubuntu 21.04 I have a bug with connection to external monitors wia dock station.
Direct connection wia HDMI works fine.
Laptop: Lenovo ThinkPad T490


STEPS TO REPRODUCE
1. Connecting monitors wia dock station
2. N/A
3. N/A

OBSERVED RESULT
At "Display Configuration" I see that monitors are detected correctly. And when mouse moved to borders it's moved like to another display, looks that monitors are available. But monitors show that "Cable is not connected". Laptop start to work very slow (long animation time, and widgets loading).
Memory and CPU consumption is almost the same as before connection to monitors.

EXPECTED RESULT
Monitors displays picture, and laptop work fast as before connection.


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Kubuntu 21.04
(available in About System)
KDE Plasma Version: 5.21.4
KDE Frameworks Version: 5.80.0
Qt Version: 5.12.2

ADDITIONAL INFORMATION
It's my working laptop, and I should decide to stay on fresh Kubuntu. Can I collect logs somehow ?

Comment 1 Włodzimierz Ciesielski 2021-06-07 07:53:43 UTC

any updates ?

Comment 2 Cuchac 2021-06-11 06:46:10 UTC

Hello,
I believe this is same issue as https://bugs.kde.org/show_bug.cgi?id=437470. I've attached logs there.

Comment 3 Włodzimierz Ciesielski 2021-06-11 11:43:50 UTC

Look that it has similar symptoms. Will see if it's the same RC. I'll follow that rapport to

Comment 4 Włodzimierz Ciesielski 2021-07-08 15:05:35 UTC

Hi,
I have upgraded plasma to 5.22.3 using:
https://9to5linux.com/you-can-now-install-kde-plasma-5-22-on-kubuntu-21-04-heres-how

Issue still exist

Comment 5 Włodzimierz Ciesielski 2021-07-09 13:29:02 UTC

Checked by Live USB: latest Manjaro (Plasma 5.21.4) and KdeNeon (Plsma 5.22.3). And all works fine.
Looks that issue exist only at Kubunu 21.04

Comment 6 Nate Graham 2021-07-09 13:40:13 UTC

Makes sense, since Kubuntu 21.04 ships an older version of Plasma than the one in Manjaro and Neon (or a newer version of Kubuntu, for that matter).

Comment 7 Włodzimierz Ciesielski 2021-07-12 12:35:21 UTC

But issue still exist on Kubunu 21.04 and newer Plasma 5.22.3

Comment 8 Włodzimierz Ciesielski 2021-07-12 13:37:32 UTC

I'll check Ubuntu 21.04 live USB, if it's problem with Plasma or Ubuntu

Comment 9 Włodzimierz Ciesielski 2021-07-12 14:27:52 UTC

On Ubuntu 21.04 the same issue. Look that issue isn't relative to KDE Plasma. Can we somehow redirect this issue to Ubuntu or should I create new one there ?

Comment 10 Włodzimierz Ciesielski 2021-07-12 17:20:33 UTC

Issue was at the kernel linux-image-5.11.0-22-generic side. Installing newer kernel linux-image-unsigned-5.13.1-051301-generic solves a problem