Ouch. Well...in that case, I'm not sure what to do on the Mesa side...perhaps a point release of KWin could fix this?
For what it's worth, KWin from git master has the slowdown with the GLX backend, but appears to work well with the EGL backend. I imagine that's because it uses eglChooseConfig, and doesn't request any samples, so Mesa gives it a proper non-MSAA config. It's just with GLX, where KWin rolls its own algorithm, that there's a problem.
Ouch. Well...in that case, I'm not sure what to do on the Mesa side...perhaps a point release of KWin could fix this?
For what it's worth, KWin from git master has the slowdown with the GLX backend, but appears to work well with the EGL backend. I imagine that's because it uses eglChooseConfig, and doesn't request any samples, so Mesa gives it a proper non-MSAA config. It's just with GLX, where KWin rolls its own algorithm, that there's a problem.