Bug 436926

Summary: Primary screen picking from SDDM is extremely unreliable
Product: [Plasma] kwin Reporter: myles.jon.gordon
Component: multi-screenAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: normal CC: nate
Priority: NOR    
Version: unspecified   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description myles.jon.gordon 2021-05-11 13:07:13 UTC 
SUMMARY
When I boot up my PC, I have to be so careful not to move my mouse the wrong way so that when Plasma loads, it doesn't pick my secondary monitor as the primary monitor. There must be some better way to implement this. When I turn on my PC from suspended, nearly always it picks my secondary monitor for the mouse to be on, and even when I go over to my main monitor and enter my password there, Plasma picks my actual secondary monitor as the primary. It's pretty much a gamble what will be the primary monitor when I boot up my PC or turn on from suspend. I am using Wayland.

STEPS TO REPRODUCE
1. Boot up PC and load up SDDM
2. Be extremely careful where my mouse is placed

1. Boot up PC from suspend
2. Pretty much always my secondary monitor is picked as the primary, despite it being my main monitor before I suspended it.

EXPECTED RESULT
I would just like for my main monitor to always be my primary monitor. I set this in System Settings, but it seems like SDDM wants to pick my primary monitor rather than me manually pick it.

SOFTWARE/OS VERSIONS
Linux: 5.12.2-arch
(available in About System)
KDE Plasma Version: 5.21.5
KDE Frameworks Version: 5.82.0
Qt Version: 5.15.2
Comment 1 Nate Graham 2021-05-11 20:49:44 UTC 
So you're saying that which screen is the primary one actually changes depending on your cursor position when you log in or resume from sleep?

Can you confirm that the primary screen setting in System Settings > Display & Monitor > Display Configuration is actually changing?
Comment 2 myles.jon.gordon 2021-05-12 07:59:35 UTC 
That's what it seems like - if it switches after suspend, the mouse cursor is always on my second monitor. Next time it happens I'll try and record it because I appreciate I'm explaining it pretty badly. I'll also check for that, thank you.
Comment 3 myles.jon.gordon 2021-05-12 09:35:45 UTC 
OK, so it seems like my idea of cursor placement being a factor isn't correct, but it just happened again where from suspend, the bottom panel was on my secondary monitor again. I entered my password on my main monitor, but yet the panel just wanted to switch and it even switched the wallpapers around! 

This is on Wayland, so perhaps I shouldn't be saying "primary" monitor, but by that I mean whatever monitor the bottom panel is on.
Comment 4 Nate Graham 2021-05-12 13:02:24 UTC 
Yes, there is no such thing as a primary monitor on Wayland. Sounds a bit like it's Bug 356225. Probably the screen gets added too late/early/whatever and triggers the bug.

*** This bug has been marked as a duplicate of bug 356225 ***