Bug 429992

Summary:	Display Configuration reset loop when disabling a certain display
Product:	[Plasma] KScreen	Reporter:	qlum <qlumreg>
Component:	common	Assignee:	kscreen-bugs-null <kscreen-bugs-null>
Status:	RESOLVED WORKSFORME
Severity:	normal	CC:	nate, plasma-bugs
Priority:	NOR	Keywords:	usability
Version:	5.20.4
Target Milestone:	1.0
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed In:

Description qlum 2020-12-03 22:15:57 UTC

SUMMARY
My center monitor (Asus VG27AQ) has the odd behavior to disconnect display output whenever it goes into standby.
This behavior is not unique to linux and also happens on Windows. While annoying this is not really a big issue.
The problem lies in how KDE handles disconnects / reconnects of displays.

Whenever it detects a change in the connected displays, it reloads the settings for that specific configuration.

This causes a loop of display configuration reloads if I disable it under display configuration.
The loop goes as follows:
display gets disabled,
Display goes into standby,
Disconnects the display,
kde reloads the config enabling the display,
display goes out of standby,
display reconnects,
kde reloads the config disabling the display,
and so forth.

While I can work around this issue, by never disabling the center monitor and just turning it off instead.
I mostly wanted to notify it being a thing.
A solution could be to put some sort of counter on reloading the display settings, such that it will not keep reloading indefinitely, or a way to disable the reloading.
I don't know how common monitors with this behavior of disconnecting are but, if there are more it may be worthwhile to build a fix for this.

If you need more info or anything else I am willing to help.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: Arch
(available in About System)
KDE Plasma Version: 5.20.4
KDE Frameworks Version: 5.76.0
Qt Version: 5.15.2

ADDITIONAL INFORMATION
Running a 4 display settup on xorg (nvidia propriatary drivers)
3x 1440p
1x 1080p
1x 155hz, 2x 144hz, 1x 60hz

Comment 1 qlum 2020-12-28 22:29:34 UTC

Another issue, to indicate that it may be more widespread: my second and third monitor (Gigabyte G27Q) disconnect / reconnect when in standby but do stay connected while turned off, this also causes flickering / config reloading.

Comment 2 Nate Graham 2021-08-17 02:01:44 UTC

Huh, thanks for notifying us.

Comment 3 Nate Graham 2022-11-08 22:14:21 UTC

Thank you for the bug report. Unfortunately we were not able to get to it yet. Can we ask you to please check if this is still an issue with Plasma 5.25 or 5.26?

If it is, please change the status to CONFIRMED when replying. If not, or if you can't because you no longer use this setup, you can change the status to RESOLVED WORKSFORME. Thanks a lot!

Comment 4 qlum 2022-11-09 14:40:23 UTC

I tested it again on plasma 5.26.2, and it seems to be solved.