Over the past several weeks there have been a number of new Linux graphics features introduced by David Airlie, a Red Hat employee and long-time X.Org contributer. Last month David began on a project rampage by bringing hybrid graphics to Linux
via code he called "vga_switcheroo" to switch between ATI/NVIDIA/Intel GPUs
without rebooting the system (though restarting the X.Org Server is needed at this time) that that code has now made its way into the mainline Linux kernel. Last week another David Airlie project was multi-GPU rendering support
for Linux that was written as a proof of concept to show a second GPU could render 3D applications onto the screen of the first GPU, regardless of the hardware vendor. This week we now have the ability to run two X.Org Servers for a multi-head setup off a single graphics card.
This code that allows two X.Org Servers to run off one graphics card is still very much a prototype like the multi-GPU rendering support, but it's working for David and patches are available. The patches go against libdrm and the Linux kernel and depend upon the graphics hardware driver using kernel mode-setting (KMS) for all of this to work out. In essence you can now easily have a two seat setup off one graphics card thanks to these DRM mapping changes and the introduction of render device nodes.
There's still a few items left on Airlie's to-do list for this feature and he's hoping someone else will pickup the work so he can move onto prototyping his next feature, but those interested can read about it on his blog