Bug 428997 - Resize non Qt apps (and even some Qt) causes flickering
Summary: Resize non Qt apps (and even some Qt) causes flickering
Status: RESOLVED FIXED
Alias: None
Product: kwin
Classification: Plasma
Component: general (other bugs)
Version First Reported In: 5.20.2
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-11-12 00:17 UTC by medin
Modified: 2021-03-20 19:56 UTC (History)
2 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In: 5.21
Sentry Crash Report:


Attachments
Resize non Qt apps (and even some Qt) causes flickering (300.30 KB, video/mp4)
2020-11-12 00:17 UTC, medin
Details

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Description medin 2020-11-12 00:17:33 UTC
Created attachment 133251 [details]
Resize non Qt apps (and even some Qt) causes flickering

When I resize some non Qt apps I see some flickering, this also happens with some Qt apps like Elisa. See attached video for more info.

NB : In the screenshot the flickering is more aggressive (I think video record tools cause flicking to increase, but in normal use the flickering exists but less than when recording)

I use :
Compositor : Enabled
Scale : Crisp (The same happens with Smooth and Accurate)
Rendering : OpenGL 2.0
Tearing : Automatic

Graphics Processor: Mesa DRI Mobile Intel GM45 Express Chipset
Driver : video-modesetting (intel driver cause more tearing and flickering)
Comment 1 Nate Graham 2021-03-20 02:47:38 UTC
Wayland or X11? Does it make a difference if you use Wayland if you're on X11 (or vice versa) or disable compositing, if you're using X11?
Comment 2 medin 2021-03-20 10:28:11 UTC
(In reply to Nate Graham from comment #1)
> Wayland or X11? Does it make a difference if you use Wayland if you're on
> X11 (or vice versa) or disable compositing, if you're using X11?

In fact after updating to 5.21, all those flickers that happen when resizing GTK apps are gone, something has changed in the latest major version, and I must say it's really good now. For simple and light GTK apps like Geany, Meld...  the resize is fast without problems, some heavy GTK apps show some slowness but without flickers during resizing but it's acceptable and I think it's app related problem.

Elisa doesn't show any flickers but resizing process is slow compared to Dolphin or Kate, the window takes some time to catch to mouse position, I think many calculations are done to adapt its UI in the background which cause the slowness.
Comment 3 Nate Graham 2021-03-20 19:56:55 UTC
Oh that's great! Glad to hear it.

The issue with Elisa is known and is an app-specific issue, not a problem with KWin.