Bug 512461 - Mouse latency increases when over certain windows
Summary: Mouse latency increases when over certain windows
Status: RESOLVED WORKSFORME
Alias: None
Product: kwin
Classification: Plasma
Component: wayland-generic (other bugs)
Version First Reported In: 6.5.3
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2025-11-22 07:21 UTC by anthonyjbarricelli
Modified: 2026-01-23 14:10 UTC (History)
1 user (show)

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


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Description anthonyjbarricelli 2025-11-22 07:21:02 UTC
SUMMARY
I noticed that the mouse latency (refresh rate?) while moving over certain windows during certain times. For example, when Firefox is loading a rather heavy page. Perhaps its during times when many redraws are happening? Can be easily reproduced with Godot in about 10 seconds.

I noticed that when you wiggle the mouse to make it bigger, the effect goes away, as in the big cursor does not suffer from this effect.

STEPS TO REPRODUCE
1. Set a monitor to a 60Hz refresh rate
2. Open Godot and make a new project
3. Select 2D Scene on the left hand side as your root node
4. Hit the play button on the top right
5. Maximize the window
6. Move cursor around on window

OBSERVED RESULT
The mouse appears to update less frequently

EXPECTED RESULT
The mouse updates as frequently as without the window

SOFTWARE/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-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 9800X3D 8-Core Processor
Memory: 64 GiB of RAM (60.5 GiB usable)
Graphics Processor 1: NVIDIA GeForce RTX 5090/PCIe/SSE2
Graphics Processor 2: NVIDIA GeForce RTX 5090/PCIe/SSE2
Comment 1 anthonyjbarricelli 2025-11-22 07:24:01 UTC
> I noticed that the mouse latency (refresh rate?) while moving over certain windows during certain times.
Yeesh, this should read as:
> I noticed that the mouse latency *INCREASES* (refresh rate? decreases) while moving over certain windows during certain times.
Comment 2 Zamundaaa 2026-01-22 19:47:06 UTC
Please attach the output of
> kscreen-doctor -o
Comment 3 anthonyjbarricelli 2026-01-23 00:07:56 UTC
(In reply to Zamundaaa from comment #2)
> Please attach the output of
> > kscreen-doctor -o

❯ kscreen-doctor -o
Output: 1 HDMI-A-1 9c4b6152-51ea-435a-a459-8cd8db8cfaab
        enabled
        connected
        priority 4
        HDMI
        replication source:0
        Modes:  1:1920x1080@60.00*!  2:1920x1080@74.91  3:1920x1080@75.00  4:1920x1080@59.94  5:1920x1080@50.00  6:1680x1050@59.95  7:1280x1024@75.03  8:1280x1024@60.02  9:1440x900@59.89  10:1280x960@60.00  11:1366x768@59.79  12:1152x864@75.00  13:1280x720@60.00  14:1280x720@59.94  15:1280x720@50.00  16:1024x768@75.03  17:1024x768@70.07  18:1024x768@60.00  19:800x600@75.00  20:800x600@72.19  21:800x600@60.32  22:800x600@56.25  23:720x576@50.00  24:720x480@59.94  25:640x480@75.00  26:640x480@72.81  27:640x480@59.94  28:640x480@59.93 
        Geometry: 3840,1080 1920x1080
        Scale: 1
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: unknown
        HDR: incapable
        Wide Color Gamut: incapable
        ICC profile: none
        Color profile source: sRGB
        Color power preference: prefer accuracy
        Brightness control: supported, set to 95% and dimming to 100%
        Color resolution: unknown
        Allow EDR: unsupported
        Sharpness control: unsupported
Output: 2 DP-1 ea79fc31-a160-4837-a943-3da19c59b8c1
        enabled
        connected
        priority 1
        DisplayPort
        replication source:0
        Modes:  29:1920x1080@60.00!  30:1920x1080@144.00*  31:1920x1080@119.98  32:1920x1080@99.93  33:1920x1080@84.90  34:1920x1080@59.94  35:1920x1080@50.00  36:1680x1050@59.95  37:1280x1024@75.03  38:1280x1024@60.02  39:1440x900@59.89  40:1280x960@60.00  41:1280x800@59.81  42:1152x864@75.00  43:1280x720@60.00  44:1280x720@59.94  45:1280x720@50.00  46:1024x768@75.03  47:1024x768@70.07  48:1024x768@60.00  49:800x600@75.00  50:800x600@72.19  51:800x600@60.32  52:800x600@56.25  53:720x576@50.00  54:720x480@59.94  55:640x480@75.00  56:640x480@59.94  57:640x480@59.93 
        Geometry: 1920,1080 1920x1080
        Scale: 1
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: unknown
        HDR: incapable
        Wide Color Gamut: incapable
        ICC profile: none
        Color profile source: sRGB
        Color power preference: prefer accuracy
        Brightness control: supported, set to 95% and dimming to 100%
        DDC/CI: disallowed
        Color resolution: unknown
        Allow EDR: unsupported
        Sharpness control: unsupported
Output: 3 DP-2 b3221f6c-ed72-4159-a506-b9a4eabdf846
        enabled
        connected
        priority 2
        DisplayPort
        replication source:0
        Modes:  58:1920x1080@60.00*!  59:1680x1050@59.95  60:1400x1050@59.98  61:1600x900@60.00  62:1280x1024@75.03  63:1280x1024@60.02  64:1440x900@59.89  65:1280x800@59.81  66:1152x864@75.00  67:1280x720@60.00  68:1024x768@75.03  69:1024x768@60.00  70:800x600@75.00  71:800x600@60.32  72:800x600@56.25  73:640x480@75.00  74:640x480@59.94 
        Geometry: 1920,0 1920x1080
        Scale: 1
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: unknown
        HDR: incapable
        Wide Color Gamut: incapable
        ICC profile: none
        Color profile source: sRGB
        Color power preference: prefer accuracy
        Brightness control: supported, set to 95% and dimming to 100%
        DDC/CI: disallowed
        Color resolution: unknown
        Allow EDR: unsupported
        Sharpness control: unsupported
Output: 4 DP-3 85ac2324-0a50-499f-b337-bcefef9a5d3a
        enabled
        connected
        priority 3
        DisplayPort
        replication source:0
        Modes:  75:1920x1080@60.00*!  76:1920x1080@74.91  77:1920x1080@75.00  78:1920x1080@59.94  79:1920x1080@50.00  80:1680x1050@59.95  81:1280x1024@75.03  82:1280x1024@60.02  83:1440x900@59.89  84:1280x960@60.00  85:1366x768@59.79  86:1152x864@75.00  87:1280x720@60.00  88:1280x720@59.94  89:1280x720@50.00  90:1024x768@75.03  91:1024x768@70.07  92:1024x768@60.00  93:800x600@75.00  94:800x600@72.19  95:800x600@60.32  96:800x600@56.25  97:720x576@50.00  98:720x480@59.94  99:640x480@75.00  100:640x480@72.81  101:640x480@59.94  102:640x480@59.93 
        Geometry: 0,1080 1920x1080
        Scale: 1
        Rotation: 1
        Overscan: 0
        Vrr: incapable
        RgbRange: unknown
        HDR: incapable
        Wide Color Gamut: incapable
        ICC profile: none
        Color profile source: sRGB
        Color power preference: prefer accuracy
        Brightness control: supported, set to 95% and dimming to 100%
        Color resolution: unknown
        Allow EDR: unsupported
        Sharpness control: unsupported
Comment 4 anthonyjbarricelli 2026-01-23 00:16:29 UTC
I actually cannot recreate this issue anymore. If nothing is jumping out from kscreen-doctor output this can be closed. Thank you
Comment 5 Zamundaaa 2026-01-23 14:10:13 UTC
> Color power preference: prefer accuracy
You probably want to set that back to the default, it's very unlikely you want the inefficiency that comes with this setting.

But yeah, if the issue doesn't happen anymore, no need to keep the bug report open. If it does happen again, just reopen it.