Bug 493233

Summary:	Maximize a window cause it no longer update framebuffer under Wayland
Product:	[Plasma] kwin	Reporter:	Rin Cat <rincat>
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED WAITINGFORINFO
Severity:	normal
Priority:	NOR
Version First Reported In:	6.1.5
Target Milestone:	---
Platform:	Gentoo Packages
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	left side is freeze dolphin at back, right side is a freeze dolphin and mouse move shadow Maximize from left to right

Description Rin Cat 2024-09-17 00:44:27 UTC

Created attachment 173746 [details]
left side is freeze dolphin at back, right side is a freeze dolphin and mouse move shadow

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SUMMARY
When I maximize a window, after the animation, the window no longer update its framebuffer. Leaves the last frame and others can draw on it, as I attached screenshot.
The window still able to response any actions, like click or keyboard, and the mouse will change to different icon like move or busy.
When the window undo the maximize, like use super + drag, everything back normal.
I am not sure what actually cause this, but I start notice it recently around plasma 6.1.


STEPS TO REPRODUCE
1. Maximize a window
2. 
3. 

OBSERVED RESULT
The window freeze and no longer update its framebuffer.

EXPECTED RESULT
Window able to update its framebuffer.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.11.0-gentoo-x86_64 
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.6.0
Qt Version: 6.7.2

ADDITIONAL INFORMATION
Under Wayland, with LLVM/clang/clang++
Intel A770 GPU

Comment 1 Vlad Zahorodnii 2024-09-18 10:30:27 UTC

Please check kwin's logs `journalctl --user-unit --boot plasma-kwin_wayland`

Comment 2 Rin Cat 2024-09-18 11:57:12 UTC

(In reply to Vlad Zahorodnii from comment #1)
> Please check kwin's logs `journalctl --user-unit --boot plasma-kwin_wayland`

I am using OpenRC, so I checked log in `~/.local/share/sddm/wayland-session.log`.
Although there are some logs like:
`The cached device pixel ratio value was stale on window update.  Please file a QTBUG which explains how to reproduce.`

But when the issue happens, there is no logs. No output at all.

Comment 3 Rin Cat 2024-09-22 10:00:47 UTC

I've noticed a strange behavior. If I first occupy half of the window close to the taskbar and then maximize it, this abnormal behavior does not occur. However, if I first occupy the half far from the taskbar and then maximize, it does appear. 

This behavior seems to be related to the floating taskbar. If you turn off floating, this problem no longer occurs.

Comment 4 Rin Cat 2024-09-22 10:01:52 UTC

Created attachment 173957 [details]
Maximize from left to right

Comment 5 Vlad Zahorodnii 2024-09-24 12:14:33 UTC

Can you provide the output of `qdbus org.kde.KWin /KWin supportInformation` when you see glitches? Also, have you enabled any non-default effect or a script?

Comment 6 Rin Cat 2024-10-03 03:23:39 UTC

After a few daily system upgrades and reset the config, I can no longer reproduce this issue.
I still don't know what the problem is, but I'm closing it now. If anyone encounters this again, please reopen it.