Bug 450921

Summary: regression in Wayland multi monitor setup
Product: [Plasma] kwin Reporter: galder <lemmyg>
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED FIXED    
Severity: major CC: aleixpol, dennis.schridde, heri+kde, notmart, ycardon
Priority: NOR    
Version First Reported In: 5.24.2   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description galder 2022-02-27 12:19:49 UTC 
SUMMARY
***
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***
I use a laptop and an external monitor(primary).
After update from 5.24.1 to 5.24.2 when I log in to the Wayland session, the external monitor works as expected showing the desktop but my laptop still displays the login screen.

If I run 
sddm-greeter --theme /usr/share/sddm/themes/breeze --test-mode
[11:46:51.691] (II) GREETER: High-DPI autoscaling not Enabled
[11:46:51.699] (WW) GREETER: QSocketNotifier: Can only be used with threads started with QThread
[11:46:51.726] (II) GREETER: Reading from "/usr/share/xsessions/plasma.desktop"
[11:46:51.726] (II) GREETER: Reading from "/usr/share/xsessions/plasmax11-dev.desktop"
[11:46:51.726] (II) GREETER: Reading from "/usr/share/wayland-sessions/plasmawayland-dev.desktop"
[11:46:51.726] (II) GREETER: Reading from "/usr/share/wayland-sessions/plasmawayland.desktop"
[11:46:51.727] (II) GREETER: Loading theme configuration from "/usr/share/sddm/themes/breeze/theme.conf"
[11:46:51.735] (EE) GREETER: Socket error:  "QLocalSocket::connectToServer: Invalid name"
[11:46:51.759] (II) GREETER: Loading file:///usr/share/sddm/themes/breeze/Main.qml...
[11:46:52.011] (II) GREETER: Adding view for "eDP-1" QRect(1920,0 1920x1080)
[11:46:52.012] (WW) GREETER: Wayland does not support QWindow::requestActivate()
[11:46:52.013] (II) GREETER: Loading file:///usr/share/sddm/themes/breeze/Main.qml...
[11:46:52.033] (WW) GREETER: QQmlEngine::setContextForObject(): Object already has a QQmlContext
[11:46:52.034] (WW) GREETER: QQmlEngine::setContextForObject(): Object already has a QQmlContext
[11:46:52.060] (II) GREETER: Adding view for "HDMI-A-1" QRect(0,0 1920x1080)

the test opens 2 login screens in my external monitor. When previously it will open one each monitor.

If  try system-settings monitor setup when I run identify in laptop screen is identified as HDMI-A-1 when should be eDP-1



STEPS TO REPRODUCE
1. login in Wayland session.
2. Note only external screen enters in the session, the laptop screen stays with login screen.
3. 

OBSERVED RESULT
the multiple screen get unusable. I cant even reconfigure manually. Even creating a new user I get the same result.

EXPECTED RESULT
screens are detected properly and working as before in 5.24.1

SOFTWARE/OS VERSIONS

Operating System: Kubuntu 21.10
KDE Plasma Version: 5.24.2
KDE Frameworks Version: 5.91.0
Qt Version: 5.15.2
Kernel Version: 5.13.0-30-generic (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i7-7700HQ CPU @ 2.80GHz
Memory: 15.5 GiB of RAM
Graphics Processor: Using Nvidia proprietary driver 510

ADDITIONAL INFORMATION
Comment 1 galder 2022-02-27 13:09:41 UTC 
It looks like is related to the login screen and having an external monitor connected.
when I login kscreen does not disappear in the laptop monitor blocking me to see the desktop.
Disconnecting the monitor works as normal.
Comment 2 Aleix Pol 2022-02-28 16:51:39 UTC 
KWin decides on which screen the different windows are placed, the algorithm KWin uses to place screens has changed recently.

Why are you using sddm-greeter --test-mode? 

Are you trying to say that they're differently placed in SDDM as well?
Comment 3 galder 2022-02-28 17:26:55 UTC 
Basically the problem is that sddm screen doesn't close it  in the laptop screen once I login in.
it looks like something has been change that now sddm doesn't handle properly the screens.
to test that locally, I used the trick you taught me. :)
when I run sddm-greeter in wayland it opens the two login windows in my external screen.
in x11, it will open as usual one window in each screen.
Comment 4 galder 2022-03-01 09:21:22 UTC 
I made a video.
I hope this helps
https://youtu.be/Y4TtEv5Pip4
Comment 5 ycardon 2022-03-01 13:21:25 UTC 
Same problem here, with the same configuration
---
Operating System: Kubuntu 21.10
KDE Plasma Version: 5.24.2
KDE Frameworks Version: 5.91.0
Qt Version: 5.15.2
Kernel Version: 5.13.0-30-generic (64-bit)
Graphics Platform: Wayland
Graphics Processor: Using Nvidia proprietary driver 510 (Nvidia prime, on demand mode)
---
I don't know if it helps, but it seems my external monitors have changed names : they used to be named "unknown DP-1" and "unknown DP-2 and they are now named "unknown DP-5-unknown" and "unknown DP-6-unknown" .
Comment 6 galder 2022-03-02 12:01:45 UTC 
removing kscreen to avoid confusion
Comment 7 galder 2022-03-08 21:06:57 UTC 
Hello,
I'm testing 5.24.3 and this issue was resolved.

Thanks for fixing it.
Galder