Comment 73 for bug 1310023

@Hamish: I should probably make nvidia-settings more robust so that it handles cases such as yours.

I wouldn't expect bbswitch to work on a desktop, although graphics offloading should still work. Right now, if bbswitch is not available or it doesn't work, the gpu-manager will change the alternatives and select mesa as a fallback.

I should make the gpu-manager a bit more tolerant, so that it will still try to do the offloading when bbswitch is not supported (or not available). I've filed LP: #1349282 and I'll work on it. This should cover your specific use case.