| Summary: | [Kwin] [Scene-OpenGL] [Wayland] When connecting 4 monitors to a system, system will stall on a blank screen after SDDM login | ||
|---|---|---|---|
| Product: | [Plasma] kwin | Reporter: | teelarr |
| Component: | scene-opengl | Assignee: | KWin default assignee <kwin-bugs-null> |
| Status: | RESOLVED UPSTREAM | ||
| Severity: | major | CC: | nate, xaver.hugl |
| Priority: | NOR | ||
| Version First Reported In: | 6.4.2 | ||
| Target Milestone: | --- | ||
| Platform: | openSUSE | ||
| OS: | Linux | ||
| Latest Commit: | Version Fixed/Implemented In: | ||
| Sentry Crash Report: | |||
| Attachments: | This is what you should see | ||
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Description
teelarr
2025-07-20 22:00:58 UTC
Just a note to say that this looks very similar to https://bugs.kde.org/show_bug.cgi?id=500819 but I am on a much higher version of Plasma, so I’m not sure if it’s related. This is 100% repro for me, issue does not happen if I unplug a fourth monitor. There's a good chance this is just caused by the driver not handling bandwidth limits properly. In Plasma 6.4, you can limit the color resolution to a lower value, please test if setting that on all screens helps. I don’t see an option to set this anywhere - should it be in display options? 🐛🧹 ⚠️ This bug has been in NEEDSINFO status with no change for at least 15 days. Please provide the requested information, then set the bug status to REPORTED. If there is no change for at least 30 days, it will be automatically closed as RESOLVED WORKSFORME. For more information about our bug triaging procedures, please read https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging. Thank you for helping us make KDE software even better for everyone! Unfortunately I do not see the color resolution option in the display settings panel. Adding this info in case this is another bug in itself. Created attachment 184505 [details]
This is what you should see
This option is not there for me, on a discussion thread I opened it was mentioned that it might not be supported on my RTX4090, this is the link that was given: https://drmdb.emersion.fr/properties/3233857728/max%20bpc It sounds like there may be multiple hardware or driver bugs here, unfortunately. I'll let the KWin folks decide if there's anything we can do about it in KWin. (In reply to Nate Graham from comment #8) > It sounds like there may be multiple hardware or driver bugs here, > unfortunately. I'll let the KWin folks decide if there's anything we can do > about it in KWin. Thank you! Please don’t hesitate if there’s anything more I can provide to help. Yeah, I think this needs to be reported at https://forums.developer.nvidia.com/c/gpu-graphics/linux - at a minimum, NVidia needs to add the "max bpc" property, so that we can limit bit depth, but drivers are supposed to do that automatically as well Sorry for the additional bump - Is there anywhere else I can report this? I'm reporting as a home user, and therefore can't sign up for an NVIDIA Developer account. I also see that 580.76.05 came with the following patch notes: "Added an "OutputBitsPerComponent" MetaMode attribute that can be used to control the number of bits per color component transmitted via a display connector. If not specified, the driver will choose an optimal color format." https://www.nvidia.com/en-us/drivers/details/252613/ Is this related? Appears to be resolved as of 580.105.08. (With the caveat that enabling all 4 monitors results in a black screen but can eventually be cancelled with the output: "Couldn’t apply display configuration: The driver rejected the output configuration" It is not longer a fatal stall that requires a forced reboot of the machine. |