Bug 472016

Summary:	Extreme flickering on a Wayland session on Plasma 6 when run on a VM
Product:	[Plasma] kwin	Reporter:	guimarcalsilva
Component:	wayland-generic	Assignee:	KWin default assignee <kwin-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	lassi.vaatamoinen, michel, nate, xaver.hugl
Priority:	NOR	Keywords:	qt6, wayland-only
Version:	git master
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:	https://invent.kde.org/plasma/kwin/-/commit/f43e45c984382a7f02c4b9a8cf4c8c1019ad193b	Version Fixed In:
Sentry Crash Report:

Description guimarcalsilva 2023-07-06 20:41:41 UTC

SUMMARY

On a VM, Plasma 6 flickers a lot on a Wayland session. X11 is fine. The cursor is also invisible. The video below illustrates the issue:
https://www.youtube.com/watch?v=QjVXg1KtpR4

I'm using Gnome Boxes with a Linux host, however, the same is true on Virtual Box on Windows.

STEPS TO REPRODUCE
1. Launch a Plasma 6 Wayland session on a virtual machine

OBSERVED RESULT

The mouse cursor is invisible and the whole image flickers

EXPECTED RESULT
No flickering

SOFTWARE/OS VERSIONS
KDE Plasma Version: 5.27.80
KDE Frameworks Version: 5.240.0
Qt Version: 6.5.1

ADDITIONAL INFORMATION
Neon Unstable July 6th 2023.

Comment 1 Zamundaaa 2023-07-17 08:39:02 UTC

I don't know about the cursor, but the flickering is caused by https://gitlab.freedesktop.org/mesa/mesa/-/issues/9375. https://invent.kde.org/plasma/kwin/-/merge_requests/4249 should fix it

Comment 2 guimarcalsilva 2023-09-10 20:26:43 UTC

New info. I tested now with Virtualbox instead of Gnome Boxes, and there's no flickering, however, the cursor is still invisible, and all the timing of the animations is also broken. Likely a bunch of bugs. If necessary I can create separate bug reports for those.

Comment 3 Zamundaaa 2023-09-10 20:42:56 UTC

Virtualbox probably sets up some sort of OpenGl acceleration by default, which will circumvent the Mesa bug. For the cursor, see bug 474298

Comment 4 Michel Le Bihan 2023-09-14 19:12:23 UTC

Hello,
I tested the `neon-developer-20230907-1341.iso` live iso in libvirt QEMU/KVM with Virtio graphics and I noticed extreme flickering, but the cursor is visible.

Comment 5 Lassi Väätämöinen 2023-10-07 22:19:31 UTC

 I tried VIrtualBOx + Plasma Wayland on  neon-unstable-20231001-1120, after doing 'apt udpate && apt dist-upgrade', and the Wayland session did not even start. After several flickers between VirtualBox screen sizes, it went back to the SDDM login screen. Syslog showed segfaults.

Comment 6 Zamundaaa 2023-10-08 18:27:05 UTC

That's a different bug, please make a separate report for that.

For the actual bug with flickering, we've included a workaround with https://invent.kde.org/plasma/kwin/-/commit/f43e45c984382a7f02c4b9a8cf4c8c1019ad193b