Happens in Kubuntu 16.04(with backports ppa, 5.6.5) and Manjaro(latest updates, 5.7.4 or 5.7.5 don't remember). GPU Radeon HD5770, OSS drivers on all systems. If it starts flickering i go to compositor settings and re-enable rendering backend. It happens with both OpenGL 2.0 and 3.1 Happens few times a week. I've made a video to demonstrate. Reproducible: Sometimes
Please provide output of: qdbus org.kde.KWin /KWin supportInformation
Created attachment 101114 [details] qdbusOutput
Couldn't uplod here, so uploaded to youtube, here's a video demonstration https://youtu.be/KXaILpQOTsk
I'm not quite certain from watching the video: it looks like it's only with the task manager?
It usually effects windows too, some of them flicker so much its possible to see the window or some elements of it behind foreground window. I'll record it when i catch it again.
Here're 2 videos that show different cases very well. Both took in the latest stable Manjaro. https://youtu.be/WnXfEld9LIQ https://youtu.be/H9uJtos07es
Created attachment 101165 [details] qdbus output from Manjaro qdbus output from the latest stable Manjaro, Plasma 5.7.4
After Manjaro updated to 5.7.5 i had this issue just once. Right now i'm on 5.8.2 and it appears the issue is gone atleast for X11 session however in Wayland i have similar trouble now. Should i make a new video and post it in wayland-generic section?
yes for wayland please report a new bug. From what I understand the problem seems to no longer happen and I set to worksforme.