Bug 398345

Summary: Black screen
Product: [Plasma] KScreen Reporter: MH2 <haagmj>
Component: commonAssignee: Sebastian Kügler <sebas>
Status: RESOLVED FIXED    
Severity: normal CC: kde, nate
Priority: NOR    
Version First Reported In: 5.13.4   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: attachment-22698-0.html

Description MH2 2018-09-07 03:20:41 UTC 
Presented with a black screen after system loads. Creating file /etc/X11/xorg.conf with specified resolution using nvidia-xconfig results in the SDDM login screen appearing correctly. However, after logging in I'm again presented with a black screen. Plasma-desktop is active, since it will respond to keyboard events. The problem has something to do with "handshaking" to obtain correct screen resolution.

I'm now running Debian Stretch with an earlier version of KDE, but the problem is the same when running Debian Buster. My PC is connected to an AVR via HDMI that is limited to 1920x1080 resolution. The AVR is then connected via HDMI to a 4k TV.

If I connect the system directly to the TV via HDMI, all is well, but I no longer have surround sound. My NVidia card, GT 710 correctly detects the TV as 2-channel and  will not output multi-channel.

I did not have any display issues with earlier NVidia cards/drivers on this system. Also, everything did work at one time running Buster, meaning the AVR resolution was correctly detected and the nvidia-driver passed multi-channel audio. However, subsequent updates to nvidia-driver, Xserver, and KDE libraries resulted in the above behavior.

I reported this bug under KWIN because I can get everything to work with a manual configuration of xorg.conf, i.e. working SDDM display with correct resolution. KWIN seems to be re-acquiring the EDID from the TV and switching to a 4k resolution which my AVR is incapable of handling.
Comment 1 David Edmundson 2018-09-07 09:22:21 UTC 
>KWIN seems to be re-acquiring the EDID from the TV and switching to a 4k resolution which my AVR is incapable of handling.

Please confirm that's the case by ssh'ing in and running xrandr

or by disabling kscreen with systemsettings -> startup -> background services with another screen.
Comment 2 Nate Graham 2022-11-08 20:24:54 UTC 
Thank you for the bug report. Unfortunately we were not able to get to it yet. Can we ask you to please see if you can reproduce the issue with Plasma 5.25 or 5.26?

If you can, please change the status to CONFIRMED when replying. Thanks a lot!
Comment 3 MH2 2022-11-09 02:50:57 UTC 
Created attachment 153609 [details]
attachment-22698-0.html

This is a really old bug. I was very surprised to receive this request. I'm now running Debian Bookworm, so I do have Plasma 5.26 installed and there are no issues.







---- On Wed, 09 Nov 2022 04:24:54 +0800 Nate Graham <bugzilla_noreply@kde.org> wrote ---



https://bugs.kde.org/show_bug.cgi?id=398345 
 
Nate Graham <mailto:nate@kde.org> changed: 
 
 What    |Removed                     |Added 
---------------------------------------------------------------------------- 
 Resolution|---                         |WAITINGFORINFO 
 Status|REPORTED                    |NEEDSINFO 
 CC|                            |mailto:nate@kde.org 
 
--- Comment #2 from Nate Graham <mailto:nate@kde.org> --- 
Thank you for the bug report. Unfortunately we were not able to get to it yet. 
Can we ask you to please see if you can reproduce the issue with Plasma 5.25 or 
5.26? 
 
If you can, please change the status to CONFIRMED when replying. Thanks a lot!
Comment 4 Nate Graham 2022-11-09 03:27:16 UTC 
Great, thanks!