Bug 485880 - Full screen in some applications causes low display refresh rate
Summary: Full screen in some applications causes low display refresh rate
Status: RESOLVED FIXED
Alias: None
Product: kwin
Classification: Plasma
Component: general (show other bugs)
Version: 6.0.4
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-04-21 07:36 UTC by deadmeu
Modified: 2024-04-25 03:31 UTC (History)
2 users (show)

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Description deadmeu 2024-04-21 07:36:13 UTC
SUMMARY
After a recent update, I have found that entering full screen in some applications (such as Firefox and VS Code), causes my displays to go "choppy" with a reduced refresh rate. I have installed these applications via Flatpak.

This does not occur in all apps, e.g. Brave (1.65.114 Flatpak) seems to be fine when in full screen.

STEPS TO REPRODUCE
1. Open Firefox/VS Code
2. Enter full screen mode (F11)
3. Observe choppiness

OBSERVED RESULT
Choppy, laggy, low refresh rate cursor movement and video playback

EXPECTED RESULT
Smooth cursor movement and video playback

SOFTWARE/OS VERSIONS
Firefox Version: 125.0.1 (Flatpak)
VS Code Version: 1.88.0 (Flatpak)
Operating System: Arch Linux 
KDE Plasma Version: 6.0.4
KDE Frameworks Version: 6.1.0
Qt Version: 6.7.0
Kernel Version: 6.8.7-arch1-1 (64-bit)
Graphics Platform: Wayland
Graphics Processor: AMD Radeon RX 7900 XT
Comment 1 deadmeu 2024-04-21 07:43:39 UTC
Strangely, I have just tried to capture a video of this bug using OBS, but can no longer reproduce it. I'll see if I can reproduce this effect and will provide an update when I can.
Comment 2 djneba 2024-04-22 08:48:04 UTC
I can confirm. I run games in full screen. Frames are dropping like crazy even though my hardware was pushing 100+ fps before. Now the framerates are about 2 times lower. Should still be playable but it stutters even at 50 fps. Looks more like 10 fps.
Comment 3 djneba 2024-04-22 08:48:52 UTC
I can confirm. I run games in full screen. Frames are dropping like crazy even though my hardware was pushing 100+ fps before. Now the framerates are about 2 times lower. Should still be playable but it stutters even at 50 fps. Looks more like 10 fps.
Comment 4 deadmeu 2024-04-22 09:01:07 UTC
I've been experiencing it again all day today. I think a reboot resets it. I have not been able to resolve it as occurred yesterday. Visually, it looks as though the refresh rate drops to around 30 HZ.

I suspect it is graphics related, as I have noticed that if I have a video playing on one display, and go full screen on another to trigger the effect, the video plays with terrible graphical artifacts. The artifacts appear as Horizontal bars across the entire video, comprised of smaller squares of various colours. When I move the mouse on the full-screen display I can see the cursor move at a choppy framerate, and the video artifacts like crazy.
Comment 5 Zamundaaa 2024-04-24 00:05:08 UTC
6.0.4.1 is out with a fix for a performance regression for fullscreen apps, did that fix this issue too?

> I suspect it is graphics related, as I have noticed that if I have a video playing on one display, and go full screen on another to trigger the effect, the video plays with terrible graphical artifacts. The artifacts appear as Horizontal bars across the entire video, comprised of smaller squares of various colours. When I move the mouse on the full-screen display I can see the cursor move at a choppy framerate, and the video artifacts like crazy.
Does that only happen while the video is full screen, and does it go away if you move a small window over the fullscreen video?
Comment 6 djneba 2024-04-24 15:38:30 UTC
I had no artifacts like the op. This new version did solve my performance problem.
Comment 7 deadmeu 2024-04-25 03:31:15 UTC
I've just updated to 6.0.4.1 and I can confirm the issue is resolved.

I think the artifacting I was experiencing was more of a symptom of the performance issue with my combination of hardware & mesa. I have often experience artifacting in some full screen games prior to this issue so I don't think any of that was related to this bug.

Thanks!