Intel + nVida simultaneously. Is it possible for Linux desktop?

I was able to get my NVIDIA card working for compute loads only, with prime set to use the Intel GPU. For the details see

https://devtalk.nvidia.com/default/topic/734737/linux/ubuntu-14-04-optimus-cuda/2/post/4831145/#4831145

Many of the solutions I’ve seen say to just change a BIOS setting, and boom, it works. But my BIOS has no such setting (DELL), and nobody really tries to explain why this works. They just tried it, and it did. But for me, it didn’t, so I dug deeper to try and figure out what exactly Prime was doing (see link).