If I try to launch something with optirun under compiz, it works.
If I try to launch something with optirun under KDE or metacity, it gives me:
[ 247.384077] [ERROR]Cannot access secondary GPU - error: [XORG] (EE) [ 247.384117] [ERROR]Aborting because fallback start is disabled.
If it matters, I'm trying to launch Portal 2 with wine
Nvidia GeForce GT540M with optimus
Acer Aspire Timeline X
Intel core i5 and 3000 Integrated Graphics