| Summary: | Tearing when refresh rate is over 120hz | ||
|---|---|---|---|
| Product: | [Plasma] kwin | Reporter: | Johan <bugskde.laurel460> |
| Component: | wayland-generic | Assignee: | KWin default assignee <kwin-bugs-null> |
| Status: | RESOLVED UPSTREAM | ||
| Severity: | normal | CC: | kdedev, xaver.hugl |
| Priority: | NOR | ||
| Version First Reported In: | 6.3.4 | ||
| Target Milestone: | --- | ||
| Platform: | Arch Linux | ||
| OS: | Other | ||
| See Also: | https://bugs.kde.org/show_bug.cgi?id=494547 | ||
| Latest Commit: | Version Fixed In: | ||
| Sentry Crash Report: | |||
| Attachments: |
The wallpaper that most often causes the tearing.
Causes some tearing at some times, but not nearly as often-wallpaper |
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Description
Johan
2025-05-12 06:12:03 UTC
That video never loads, can you upload it somewhere else? My hunch here would be that it's a driver synchronization bug though. I was able to view the video with DeGoogled Chromium, but it's best to upload it somewhere else or ideally attach a video to this bug report. Based on the tearing I saw in the Steam window, the graphical glitches look exactly like bug 494547, which involves the nouveau drivers I'm not able to reproduce this on git-master Wayland, on a monitor with the refresh rate set to 144Hz and 150% scaling nVidia GPU, proprietary drivers v 570.144 The monitor is 1440p so this likely only presents with 4k Hi there! Absolutely, can you try this link: https://drive.proton.me/urls/63Y64J70ZM#YIlJNGwTOuZk I also recently found someone else with this issue (he also has a 4K 240hz monitor) on the CachyOS subreddit: https://www.reddit.com/r/cachyos/comments/1kii9t4/why_does_cachyos_hate_my_monitor_screen/ I suspected at first it was related to DSC but as my monitor uses that regardless of resolution and refresh rate, it isn't related to that. It's worth to note that I am not using the nouveau drivers, instead I use the "open" drivers from Nvidia. What should the next step be? Anything I can provide or should I create a bug report somewhere else? Ok, that definitely looks like a synchronization issue. I also found https://www.reddit.com/r/linux_gaming/comments/1kk04vg/screen_tearing_when_i_using_anything_above_60_fps/, about the same thing happening on hyprland, so it's at least very likely to be a bug in the driver. You can report this at https://forums.developer.nvidia.com/c/gpu-graphics/linux Hi @Zamundaaa, thanks for the investigation, but I wanted to understand why you think it is a driver synchronization issue? I could understand if it was due to that if we had multiple monitors enabled, but I see this issue with only one monitor enabled, so then the compositor shouldn't be confused due to multiple various refresh rates (if I'm not mistaken of course). Another thing I noticed regarding this error is that it seems to be somewhat affected by the wallpaper I'm using. In this video, you can see that when I switch to the black wallpaper, the issue start to appear, but as soon as I switch back to my colored wallpaper, it stops happening. This is really bizarre so let me add the video here: https://drive.proton.me/urls/CYQQKSHD9R#yHdPLBFlzEHl I have also attached the wallpapers in question so that you can try for yourself if you can make it happen (I suspect not but worth a shot). Created attachment 181293 [details]
The wallpaper that most often causes the tearing.
Created attachment 181294 [details]
Causes some tearing at some times, but not nearly as often-wallpaper
What you're seeing is not actually tearing, that looks different and never shows anything below the current window. What you're seeing is almost certainly that the driver doesn't report correctly when compositing is complete, which makes KWin send it to the screen while it's still rendering. If the image is shown too early, when it's not done rendering yet, then parts of the screen can have windows be see-through like in your videos. Because this is a race between rendering speeds and sending the image to the display, a lot of random-ish things can make it better or worse. |