Bug 496720

Summary:	Display shows as attached even though it has been physically disconnected
Product:	[Plasma] kwin	Reporter:	Ondřej Mach <ondrej.mach>
Component:	general	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	xaver.hugl
Priority:	NOR
Version First Reported In:	6.2.3
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	Output of drm_info Output of kscreen-doctor -o

Description Ondřej Mach 2024-11-26 20:24:16 UTC

SUMMARY
After Thunderbolt dock is disconnected with laptop lid closed, the screen sometimes shows up as connected (shown in kscreen). Logging out and logging back in fixes the issue. I cannot reproduce this bug every time, but happens quite often (at least 1 out of 10 tries). As a result, laptop does not go to sleep and drains the battery. Also, when the dock is reconnected, the display stays black. I think the bug must have been introduced with plasma 6.2.0 or later, I'm pretty sure I did not encounter it in 6.1.x. 

STEPS TO REPRODUCE
1. Have laptop connected to a Thunderbolt dock (I used Thinkpad dock gen 2)
2. Have a monitor connected to the dock (I had Gigabyte M2ýQ over HDMI)
3. Close the lid of the laptop
4. Disconnect the monitor
5. Open up the laptop and evaluate

OBSERVED RESULT
The monitor shows up as connected

EXPECTED RESULT
The monitor does not show up

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 40
KDE Plasma Version: 6.2.3
KDE Frameworks Version: 6.8.0
Qt Version: 6.7.2
Kernel Version: 6.11.8-200.fc40.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 8 × Intel® Core™ i5-8350U CPU @ 1.70GHz
Memory: 31.2 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620
Manufacturer: LENOVO
Product Name: 20L6SJAC00
System Version: ThinkPad T480

Comment 1 Zamundaaa 2025-02-10 17:35:55 UTC

When it happens, please get the output of drm_info and "kscreen-doctor -o" and attach both here

Comment 2 Ondřej Mach 2025-02-19 07:06:21 UTC

Created attachment 178566 [details]
Output of drm_info

Comment 3 Ondřej Mach 2025-02-19 07:07:08 UTC

Created attachment 178567 [details]
Output of kscreen-doctor -o

Comment 4 Bug Janitor Service 2025-03-06 03:47:21 UTC

🐛🧹 ⚠️ 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!

Comment 5 Zamundaaa 2026-01-19 20:12:01 UTC

Sorry, this got lost in my emails. The drm_info output shows the display as still connected, so this problem is on a lower level.
If you still have the problem, you can report it at https://gitlab.freedesktop.org/drm/i915/kernel/-/issues