Bug 503458

Summary:	Significant flickering in some application windows when using "Prefer efficiency" color accuracy on Nvidia
Product:	[Plasma] kwin	Reporter:	Andrew Gunnerson <accounts+kde>
Component:	colour-management	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	AaronBrittain, kdedev, nate, xaver.hugl
Priority:	NOR
Version First Reported In:	6.3.4
Target Milestone:	---
Platform:	Fedora RPMs
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Andrew Gunnerson 2025-04-28 05:10:56 UTC

SUMMARY

When using the "Prefer efficiency" color accuracy option, the bottom half of an application window sometimes has significant flickering. I'm consistently able to reproduce this when maps.google.com is open in Firefox. However, when changing to the "Prefer color accuracy" option, the issue goes away. Dropping the refresh rate from 5120x2160@165Hz to 5120x2160@100Hz also makes the issue go away.

Neither HDR vs SDR nor the VRR settings have any impact.

I've reported this to Nvidia at https://forums.developer.nvidia.com/t/flickering-graphics-corruption-and-loss-of-signal-with-nvidia-4090-and-5k2k-screen-lg-45gx950a-b-aus/331111, but I'm also reporting the issue here because when a window flickers, I can see the contents of the windows behind it. I'm not sure if there might be a potential compositing issue.

I recorded a couple videos to demonstrate the issue:
1. https://youtu.be/ybtIBgTleqQ - Shows the issue with both the "Prefer efficiency" and "Prefer color accuracy modes"
2. https://youtu.be/chNFBBxxoVo - Shows the extent of the flickering and how the contents behind the flickering window are visible

STEPS TO REPRODUCE
1. Open maps.google.com in Firefox
2. Split the screen and put the Firefox window on the right half (seems to happen more frequently this way)
3. Drag the map around

OBSERVED RESULT

Significant flickering with the contents of windows underneath being visible when the flickering occurs

EXPECTED RESULT

No flickering

SOFTWARE/OS VERSIONS

Operating System: Fedora Linux 42
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.13.0
Qt Version: 6.9.0
Kernel Version: 6.14.3-300.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 32 × AMD Ryzen 9 9950X3D 16-Core Processor
Memory: 93.9 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 4090
Nvidia driver versions: Happens in both 575.51.02 (beta) and 570.133.07 (stable)
Monitor: LG 45GX950A-B.AUS

ADDITIONAL INFORMATION

I've tried swapping out both the monitor and the computer. I tried using the same computer with an LG C1 OLED TV (3840x2160@120Hz). I also tried using the same monitor with a different computer (Fedora 42 still), but with an Intel iGPU. The issue is not reproducible in either scenario.

Comment 1 TraceyC 2025-04-29 00:15:05 UTC

I'm able to reproduce this with Plasma 6.3.4 on a laptop with an nvidia gpu. It's not as pronounced on my display, 3440x1440, which can only go to a refresh rate of 144Hz
I didn't notice flickering until I set a bottom panel to float and autohide, as in the video
I also noticed the desktop icons were shown briefly when the window flickered
nvidia driver 570.144

Unfortunately I can't properly test this with an amd gpu. The laptop that has it can't drive a monitor with a refresh rate greater than 60Hz. I didn't see any flickering with that (git-master)

Hopefully others are able to test this with different gpus

Comment 2 Aaron Brittain 2025-06-20 15:31:36 UTC

(In reply to TraceyC from comment #1)
> I'm able to reproduce this with Plasma 6.3.4 on a laptop with an nvidia gpu.
> It's not as pronounced on my display, 3440x1440, which can only go to a
> refresh rate of 144Hz
> I didn't notice flickering until I set a bottom panel to float and autohide,
> as in the video
> I also noticed the desktop icons were shown briefly when the window flickered
> nvidia driver 570.144
> 
> Unfortunately I can't properly test this with an amd gpu. The laptop that
> has it can't drive a monitor with a refresh rate greater than 60Hz. I didn't
> see any flickering with that (git-master)
> 
> Hopefully others are able to test this with different gpus

I'm experiencing this as well on my 240 hz display.

Operating System: Arch Linux
KDE Plasma Version: 6.3.5
KDE Frameworks Version: 6.15.0
Qt Version: 6.9.1
Kernel Version: 6.15.2-arch1-1 (64-bit)
Graphics Platform: Wayland
Processors: 32 × Intel® Core™ i9-14900K
Memory: 62.5 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 4090
Nvidia driver versions: Happens in both 575.51.02 (beta) and 570.133.07 (stable)
Monitor: ASUSTek PG32UCDM (3840x2160 240 hz)

However, changing the color accuracy did not change the behavior. I don't have the issue on any of my 60 hz monitors. Were you ever able to find a solution?

Comment 3 TraceyC 2025-06-20 19:31:32 UTC

(In reply to Aaron Brittain from comment #2)
> However, changing the color accuracy did not change the behavior. I don't
> have the issue on any of my 60 hz monitors. Were you ever able to find a
> solution?

Thanks for the update. This is waiting on a developer to investigate and fix. Unfortunately I don't know of a workaround.

Comment 4 Zamundaaa 2025-08-11 13:02:25 UTC

> I've reported this to Nvidia at https://forums.developer.nvidia.com/t/flickering-graphics-corruption-and-loss-of-signal-with-nvidia-4090-and-5k2k-screen-lg-45gx950a-b-aus/331111, but I'm also reporting the issue here because when a window flickers, I can see the contents of the windows behind it. I'm not sure if there might be a potential compositing issue.
Looks like NVidia has found the issue and will fix it in their driver :)