Bug 485170

Summary:	Plasma 6 often (but not always) fails to launch when using proprietary Nvidia drivers
Product:	[Plasma] kwin	Reporter:	Andy Hall <kde>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	xaver.hugl
Priority:	NOR
Version First Reported In:	6.0.3
Target Milestone:	---
Platform:	unspecified
OS:	Other
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Logs from failed login Logs from successful login

Description Andy Hall 2024-04-07 05:11:02 UTC

Created attachment 168235 [details]
Logs from failed login

SUMMARY
Sometimes when I boot my computer and try to log in to KDE Plasma via SDDM, I get a black screen for about 10 seconds and then get kicked back to SDDM. I can try logging in again, but the behavior is the same.

There seems to be roughly a 50% chance of this happening on each boot - sometimes a reboot will fix it and I can log in normally, while other times I have to reboot several times before I get lucky enough to log in.

If I re-enable Nouveau I can usually get to a desktop consistently, but unfortunately I can't stick with Nouveau drivers because they leave one of my two monitors blank. I otherwise haven't had any noticeable issues with the Nvidia drivers.

This leads me to believe that the problem is something with the interaction between the Nvidia drivers and Plasma, but I don't know how to narrow it down. Let me know which logs would be the most helpful to collect.

STEPS TO REPRODUCE
1. Boot my computer
2. Type my password into SDDM and press enter

OBSERVED RESULT
The screen goes black for about 10 seconds, then I see SDDM again. I can try logging in again, but the behavior is the same until I reboot.

EXPECTED RESULT
KDE Plasma desktop should launch.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora 40 KDE spin
KDE Plasma Version: 6
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
- Fedora 40 KDE spin
- Clean install (did not upgrade from Fedora 39)
- KDE Plasma 6 desktop (Wayland)
- Nvidia GeForce GTX 1070
- Nvidia driver nvidia-kmod-550.67-1.fc40.src.rpm from rpmfusion-nonfree
- Fractional scaling on one monitor (100% on left monitor, 125% on right monitor)

I also experienced this problem with the Fedora 40 branch of Kinoite. I assumed it was a Kinoite issue and installed the standard KDE spin, but had the same problem.

I didn't have this issue with Fedora 39.

I also reported this on the Red Hat Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2272429

Comment 1 Andy Hall 2024-04-07 05:11:24 UTC

Created attachment 168236 [details]
Logs from successful login

Comment 2 Zamundaaa 2024-04-07 18:02:31 UTC

> Mar 31 22:44:10 fedora kwin_wayland[1671]: kwin_xwl: /tmp/.X11-unix does not exist. Please check your installation
> Mar 31 22:44:10 fedora kwin_wayland[1671]: Failed to establish X11 socket
This is why it's crashing. I don't know what would cause that though

Comment 3 Andy Hall 2024-04-08 04:26:36 UTC

Thanks, that helped me narrow down my logs and figure out what happened. This was a problem I caused for myself - I had created a systemd service that created an ordering cycle, so different services were failing to start up on each boot, and sometimes that included some prerequisites for Xwayland.