After upgrading from 5.14 to 5.15, opengl compositing has stopped working with the nouveau driver. Transparency effects are gone and windows are slow to move. I'm not sure how to debug this.
Does compositing work with the proprietary NVIDIA driver?
I don't know -- I've never had it installed and I'm not going to. I'm using the Xrender rendering backend now. It works pretty well, but it's not fast and videos are tearing.
> Transparency effects are gone Hmm, can you post otuput of `qdbus org.kde.KWin /KWin supportInformation`?
I first updated to 5.15 about a month ago or so, from an unofficial copr repository. I immediately noticed the missing opengl compositor and went back to 5.14 as I couldn't make things work. I updated to the official Fedora 5.15 a couple of days before posting this bug, and was disappointed to see the same problem that I still couldn't solve. Xrender is fine, but I still reported the bug. Just now, I changed to opengl to get the list you asked for, and it just works! Something must have changed on my system quite recently, I'm guessing kernel or mesa. So I'm pretty happy with how quickly you solved my problem. Thanks!
Okay, cool. Marking as works for me.
Created attachment 119875 [details] support information when using opengl 2.0
It stopped working after some reboots, so now I'm questioning if it actually worked earlier. I've tried using older kernels with no result. I've attached the support information. One thing that sticks out is "OpenGL vendor string: VMware, Inc." which seems incorrect and odd.
It means that you're using the software renderer, which explains lagginess mentioned in the first comment.