Bug 402688

Summary:	Stuttering animations on the DRM platform
Product:	[Plasma] kwin	Reporter:	Vlad Zahorodnii <vlad.zahorodnii>
Component:	platform-drm	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal
Priority:	NOR
Version First Reported In:	git master
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Vlad Zahorodnii 2018-12-29 20:59:30 UTC

SUMMARY
If several windows are open, then pretty much all animations stutter because `time` in prePaintScreen and prePaintWindow is bigger than vblank interval.

STEPS TO REPRODUCE
1. Start KDE Plasma on Wayland.
2. Launch several applications (e.g. Firefox, Dolphin, Konsole, etc).
   In my case, it's enough to open 5-6 apps.

OBSERVED RESULT
Choppy animations.

EXPECTED RESULT
Smooth animations.

SOFTWARE/OS VERSIONS
KDE Plasma Version: 5.14.80
KDE Frameworks Version: 5.53
Qt Version: 5.12.0

ADDITIONAL INFORMATION
With 30 windows being open, animations still look smooth in the nested KWin/Wayland compositor.

Comment 1 Vlad Zahorodnii 2018-12-29 21:02:31 UTC

It doesn't matter what standalone compositor is when running the nested compositor.

Comment 2 Vlad Zahorodnii 2019-01-11 12:15:01 UTC

So, apparently it takes too much time to render each frame, which is kinda weird.

Marking it as invalid.