Bug 425046

Summary: kscreen does not init multiple screens properly the first time
Product: [Plasma] KScreen Reporter: Siddhartha <kde>
Component: commonAssignee: kscreen-bugs-null <kscreen-bugs-null>
Status: RESOLVED FIXED    
Severity: major    
Priority: NOR    
Version First Reported In: git   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: system and kscreen logs

Description Siddhartha 2020-08-05 18:00:57 UTC
Created attachment 130664 [details]
system and kscreen logs

SUMMARY
I have 2 external screens that I connect to my laptop using a USB-C dock.

1) When I connect the dock to the laptop, kscreen initially brings up plasma on all screens as expected.
2) But within seconds, the external screens are deinitialized (output stops and they turn off), while the laptop screen is frozen. I've to disconnect the dock to get the laptop screen responding again. 
3) When I connect the dock again, this time the external screens are not initalized and I've to manually go and enable them from either the display settings or using the xrandr cli, after which the multiscreen setup works properly.
4) Sometimes, it takes multiple cycles of steps 1-3 to get the external screen to work.

I've attached the system logs that shows 3-4 tries before I could get the screens working.

All my plasma packages are git master. I'm willing to help debug this and try out patches to finally resolve this annoying bug that I face almost everyday.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.19.80 (kscreen-git r1266.65f342d-1)
KDE Frameworks Version: 5.73.0
Qt Version: 5.15.0
Kernel Version: 5.7.11-arch1-1
Comment 1 Siddhartha 2021-09-17 20:10:42 UTC
Seems to be working fine for now.