Bug 460974

Summary:	Black screen for a while if session unlocked during the "unlock without password" time
Product:	[Unmaintained] kscreenlocker	Reporter:	Iyán M. V. <me>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED FIXED
Severity:	minor	CC:	bshah, nate
Priority:	NOR	Keywords:	wayland-only
Version First Reported In:	5.26.90
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Iyán M. V. 2022-10-25 09:29:27 UTC

SUMMARY
Since Plasma 5.26, if I move the mouse or press a key when the session just got automatically locked, the result is a black screen for a few seconds. After that, the session is unlocked and everything works as expected. I can only reproduce this issue with Wayland.


STEPS TO REPRODUCE
1. Enable "lock screen automatically"
2. Set a value, for example, 5 seconds to "Allow unlocking without password"
3. Wait till session is automatically locked
4. Move the mouse or press any key

OBSERVED RESULT
A black screen and unresponsive system for a few seconds (~10s).

EXPECTED RESULT
Same behavior as with previous versions of Plasma. System is immediately unlocked and responsive.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.26.1
KDE Frameworks Version: 5.99.0
Qt Version: 5.15.6
Kernel Version: 6.0.3-arch3-1 (64-bit)
Graphics Platform: Wayland
Processors: 8 × 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
Memory: 15.4 GiB of RAM
Graphics Processor: Mesa Intel® Xe Graphics
Manufacturer: LENOVO
Product Name: 20XYCTO1WW
System Version: ThinkPad X1 Yoga Gen 6

Comment 1 Nate Graham 2022-11-04 21:45:53 UTC

Can reproduce on Wayland.

Comment 2 Iyán M. V. 2023-03-14 20:58:07 UTC

Another hint about this issue that I just realized. It seems to be related to the graphics driver. Even though I can reproduce on my laptop with an Intel integrated graphics card, I cannot observe the same thing (also on Wayland) with an AMD graphics card.

Comment 3 Iyán M. V. 2023-07-05 07:47:22 UTC

I don't know if some changes in 5.26.7 fixed this, or if it was fixed by changes in mesa or the kernel. In any case, I can't reproduce this issue in any of my systems (with AMD and Intel graphics).

Operating System: Arch Linux 
KDE Plasma Version: 5.27.6
KDE Frameworks Version: 5.107.0
Qt Version: 5.15.10
Kernel Version: 6.4.1-arch2-1 (64-bit)
Graphics Platform: Wayland
Processors: 8 × 11th Gen Intel® Core™ i5-1135G7 @ 2.40GHz
Memory: 15.3 GiB of RAM
Graphics Processor: Mesa Intel® Xe Graphics
Manufacturer: LENOVO
Product Name: 20XYCTO1WW
System Version: ThinkPad X1 Yoga Gen 6