Bug 375567

Summary:	KWin vsync broken with Vulkan applications
Product:	[Plasma] kwin	Reporter:	tempel.julian
Component:	scene-opengl	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal	Flags:	mgraesslin: X11+
Priority:	NOR
Version First Reported In:	git master
Target Milestone:	---
Platform:	openSUSE
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description tempel.julian 2017-01-25 23:17:12 UTC

When I run a Vulkan game such as vkquake or Talos Principle, tearing occurs with enabled KWin compositing. This shouldn't happen, since vsync setting of KWin is set to either always repaint or reuse of image parts.
This does only occur with Vulkan applications, OpenGL games are fine (applications are not allowed to block compositing).
Doesn't seem to be limited to certain proprietary Nvidia driver versions.
As a workaround, the vsync compositing for such applications can be enabled by reenabling it via hotkey (turning it off and on again).

I'm on this repo currently (but I think it alo occurs with latest 5.8 stable version):
http://download.opensuse.org/repositories/KDE:/Unstable:/Frameworks/openSUSE_Factory/

Comment 1 Martin Flöser 2017-01-26 05:54:28 UTC

Tearing in the Vulkan window or in the complete screen?

I myself have not been able to run any Vulkan applications yet and our code is not yet adjusted it adjustments are needed

Comment 2 tempel.julian 2017-01-26 12:46:12 UTC

It seems the whole screen is affected. When I run the application windowed and move another window (e.g. normal Dolphin window) on top of it, the window on top tears as well.
The tearing also only occurs at the very same position, near to the top of the screen.

vkquake is a very compact program which may be helpful for quick tests:
https://github.com/Novum/vkQuake

Comment 3 tempel.julian 2018-08-24 17:55:38 UTC

Closing, as it apparently is an issue of the Nvidia driver.