After an update to Plasma 5.20.4, Kwin has started to either fail to start completely, or starts with compositor disabled.
KDE Plasma Version: 5.20.4
KDE Frameworks Version: 5.77.0
Qt Version: 5.15.2
Terminal output after running "kwin --replace": https://pastebin.com/92FCSuV7
In order to be able to start Kwin properly with composition, I had to go into ~/.config/kwinrc and set "OpenGLIsUnsafe" to "false" under [Compositing]
(In reply to Vlad Zahorodnii from comment #1)
No, it's an intel HD. Specifically as per inxi -G it's:
OpenGL: renderer: Mesa DRI Intel HD Graphics 4400 (HSW GT2) v: 4.5 Mesa 20.3.2
I had similar issue seemingly out of nowhere. It was working fine for months, then suddenly I started getting "kwin_core: Compositing is not possible".
I'm on Arch Linux, I updated some packages like I do everyday, but not kwin package itself. I don't know if the update is the root cause.
> In order to be able to start Kwin properly with composition, I had to go
> into ~/.config/kwinrc and set "OpenGLIsUnsafe" to "false" under [Compositing]
Setting this to "false" fixed it for me. When I looked at it, it was set to "true", but I don't know how it was set when the system was working before.
Yeah, this means KWin thinks your openGL capabilities are too unstable to do compositing. See Bug 452344.
*** This bug has been marked as a duplicate of bug 452344 ***