I have an older Sony VAIO Z 590 laptop with switchable graphics between Intel and Nvidia GeForce 9300M. It is NOT Optimus. I did a clean install of Ubuntu 12.04. Everything works, but it's using Unity 2D with the Intel drivers. I've tried loading the Nvidia drivers from "Additional Drivers", but it says "this driver is activated but not currently in use".

When I run "nvidia-settings", an error window pops up to say "You do not appear to be using the NVIDIA X drivers." "lspci" shows both graphics cards. Let me know if I should add more info.

How do I get the Nvidia graphics and Unity 3D working?

More info:

$ lshw -short -class display

H/W path       Device  Class       Description
============================================== 
/0/100/1/0             display     G98 [GeForce 9300M GS] 
/0/100/2             display     Mobile 4 Series Chipset Integrated Graphics C

$ glxinfo
name of display: :0
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Error: couldn't find RGB GLX visual or fbconfig

Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".
Xlib:  extension "GLX" missing on display ":0".

Excerpts from Xorg.0.log:

[    16.373] (II) LoadModule: "glx"
[    16.373] (II) Loading /usr/lib/x86_64-linux-gnu/xorg/extra-modules/libglx.so
[    16.386] (II) Module glx: vendor="NVIDIA Corporation"
[    16.386]    compiled for 4.0.2, module version = 1.0.0
[    16.386]    Module class: X.Org Server Extension
[    16.386] (II) NVIDIA GLX Module  295.49  Tue May  1 00:09:10 PDT 2012

[    16.608] (II) NVIDIA dlloader X Driver  295.49  Mon Apr 30 23:48:24 PDT 2012
[    16.608] (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs

[    17.693] (EE) Failed to initialize GLX extension (Compatible NVIDIA X driver not found)