Comment 5 for bug 700646

My guess is that the problem is much worse than just lack of driver support, because if you can't turn the intel card off via the BIOS, you can't use the nvidia card because the video output is driven by the intel card, meaning it's not as simple as just writing a driver for the nvidia card - you also need to be able to copy the output back to the intel card's framebuffer. (eg look http://ubuntuforums.org/showthread.php?t=1657660.)

The root cause is actually that there is no support for optimus in either the proprietary or open-source drivers, and there is unlikely to be any for some time because (a) nvidia are refusing to support it or to provide information about how to support it, and (b) you simply cannot turn it off unless there is hardware support switchable via the BIOS to do so. It's a complete disaster for nvidia cards in linux.