Aunque es posible usar esta función mediante Bumblebee, en los drivers 319.12 de NVidia ya podremos tener la función oficial en nuestros PC con GNU/Linux.
Por ahora los drivers están fase beta, pero pueden ser descargados desde la web oficial para ir probando.
The Nvidia 319.12 beta Linux display driver changelog doesn't explicitly mention Optimus support, however, the following can be found in the release notes:
"Added initial support for RandR 1.4 Provider objects with the Source Output capability, which can be used to render the desktop on an NVIDIA GPU and display it on an output connected to a provider with the Sink Output capability, such as an Intel integrated graphics device or a DisplayLink USB-to-VGA adapter".
Further more, the Nvidia 319.12 beta graphics drivers README gives some extra info on the graphics display offloading with RandR 1.4:
"Version 1.4 of the X Resize, Rotate, and Reflect Extension (RandR 1.4 for short) adds a way for drivers to work together so that one graphics device can display images rendered by another. This can be used on Optimus-based laptops to display a desktop rendered by an NVIDIA GPU on a screen connected to another graphics device, such as an Intel integrated graphics device or a USB-to-VGA adapter."
To be able to make use of the initial Optimus support in the latest Nvidia Linux graphics drivers, you'll need Xorg 1.13 or higher, xrandr command line utility version 1.4.0, a custom xorg.conf configuration which you can find in the drivers README, Linux Kernel with CONFIG_DRM enabled and the appropriate driver interfaces present (more on that, in the same README) and obviously, an Optimus-based laptop.
For now, the latest Nvidia 319.12 beta drivers don't work in Ubuntu by default, not even in Raring, because while Ubuntu has RandR 1.4, the xrandr command line utility version is 1.3.5. Further more, I'm not sure if the Ubuntu Kernel supports it (see above).
Noticia: http://www.webupd8.org/2013/04/nvidia-releases-linux-graphics-drivers.html
NVidia: http://www.nvidia.com/object/linux-display-amd64-319.12-driver.html
Aur(Arch): https://aur.archlinux.org/packages/nvidia-beta/
