Bug 512591 - Low application frame rate causes low cursor frame rate when tearing is allowed
Summary: Low application frame rate causes low cursor frame rate when tearing is allowed
Status: REPORTED
Alias: None
Product: kwin
Classification: Plasma
Component: wayland-generic (other bugs)
Version First Reported In: unspecified
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords: wayland-only
Depends on:
Blocks:
 
Reported: 2025-11-25 13:46 UTC by he3als
Modified: 2025-11-25 13:47 UTC (History)
0 users

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:

Attachments
Video that demonstrates the issue (2.76 MB, video/mp4)
2025-11-25 13:46 UTC, he3als 		Details
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Description he3als 2025-11-25 13:46:18 UTC 
Created attachment 187158 [details]
Video that demonstrates the issue

SUMMARY
When screen tearing is allowed in fullscreen and enabled for an app, the cursor's frame rate appears to depend on the application's frame rate.

STEPS TO REPRODUCE
1. Enable "Screen tearing: Allow in fullscreen windows" in Display and Monitor
2. Force allow tearing for the application you are testing (for example through Window Rules)
3. Fullscreen the application

OBSERVED RESULT
Lower application frame rates cause the cursor to also run at a lower frame rate.

EXPECTED RESULT
The mouse cursor should be tied to the monitor's refresh rate, not the application's frame rate.

SOFTWARE AND OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 6.5.3
KDE Frameworks Version: 6.20.0
Qt Version: 6.10.0
Kernel Version: 6.17.8-zen1-1-zen (64-bit)
Graphics Platform: Wayland
Processors: 8 x 12th Gen Intel Core i7-12700K
Memory: 16 GiB of RAM (15.4 GiB usable)
Graphics Processor: NVIDIA GeForce RTX 3060 Ti
Graphics Driver: nvidia-dkms 580.95.05-1 (proprietary)

ADDITIONAL INFORMATION
I am using a 240 Hz monitor, so this might not be noticeable at lower refresh rates. I tried unplugging my 75 Hz second monitor, but this made no difference. Enabling adaptive sync or disabling triple buffering does not change the behavior.

See the video attached for a visual demonstration of this.