Bug 478659

Summary:	Choppy cursor movement at high refresh rate
Product:	[Plasma] kwin	Reporter:	Jake Hutchinson <jake>
Component:	input	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	xaver.hugl
Priority:	NOR	Keywords:	qt6
Version First Reported In:	5.90.0
Target Milestone:	---
Platform:	Arch Linux
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	KWin Output Config

Description Jake Hutchinson 2023-12-17 18:25:17 UTC

SUMMARY

Cursor appears to be rendered at 60Hz when using a high refresh rate display (144Hz) when using Plasma 6.0 Beta 1 in Wayland.

STEPS TO REPRODUCE

1. Launch plasma-wayland-session with a high refresh rate display
2. Observe cursor movement

OBSERVED RESULT

Cursor movement at 60Hz.

EXPECTED RESULT

Smooth cursor movement at 144Hz.

SOFTWARE/OS VERSIONS

Linux/KDE Plasma:  Arch Linux
KDE Plasma Version: 5.90.0-3
KDE Frameworks Version: 5.246.0
Qt Version: 6.6.1

ADDITIONAL INFORMATION

Possibly related to mixed refresh rate multi-monitor (144Hz and 60Hz monitors), will update with more information.

Comment 1 Zamundaaa 2023-12-17 20:17:47 UTC

What hardware is this on? Also, please attach ~/.config/kwinoutputconfig.json

Comment 2 Jake Hutchinson 2023-12-17 21:46:55 UTC

Created attachment 164262 [details]
KWin Output Config

CPU: Ryzen 5700x / 32GB RAM
GPU: Radeon 6800xt
Mouse: Logitech GPX

I should've added that cursor movement can be smooth when an application is maximised (I've been able to replicate this with Firefox so far, not with KDE applications) but when the cursor moves over the desktop it can lag. 

Let me know if you need any more info :)

Comment 3 Zamundaaa 2023-12-18 17:06:57 UTC

Ah, your problem is caused by https://gitlab.freedesktop.org/drm/amd/-/issues/3034. Turning adaptive sync down to automatic should be a viable workaround for now

Comment 4 Jake Hutchinson 2023-12-18 19:04:41 UTC

(In reply to Zamundaaa from comment #3)
> Ah, your problem is caused by
> https://gitlab.freedesktop.org/drm/amd/-/issues/3034. Turning adaptive sync
> down to automatic should be a viable workaround for now

Thanks that fixed it!