KWin no longer compositing?

[Andrew]

I found rather wonky X after the xorg-server upgrade until I
re-installed nvidia-driver, but then I see output mentioned in your
first link:

OpenGL vendor string:                   NVIDIA Corporation
OpenGL renderer string:                 Quadro FX 580/PCI/SSE2
OpenGL version string:                  3.3.0 NVIDIA 285.05.09
OpenGL shading language version string: 3.30 NVIDIA via Cg compiler
Driver:                                 NVIDIA
Driver version:                         285.5.9
GPU class:                              Unknown
OpenGL version:                         3.3
GLSL version:                           3.30
X server version:                       1.7.7
Direct rendering:                       yes
Requires strict binding:                no
GLSL shaders:                           yes
Texture NPOT support:                   yes
OpenGL vendor string:                   NVIDIA Corporation
OpenGL renderer string:                 Quadro FX 580/PCI/SSE2
OpenGL version string:                  3.3.0 NVIDIA 285.05.09
OpenGL shading language version string: 3.30 NVIDIA via Cg compiler
Driver:                                 NVIDIA
Driver version:                         285.5.9
GPU class:                              Unknown
OpenGL version:                         3.3
GLSL version:                           3.30
X server version:                       1.7.7
Direct rendering:                       yes
Requires strict binding:                no
GLSL shaders:                           yes
Texture NPOT support:                   yes


Doesn't help I suppose if you're not using an Nvidia card and the
binary driver...