Note that this is Tegra related, which might explain their new-found eagerness to help (unlike desktop, they don't fully "own" the mobile high performance chips market yet, and it moves very fast)
As far as I understand it, this set of patches allows you to (or at least aims in the longer term to) run Nouveau user space on top of Nvidia Tegra Kernel drivers (did anyone read the code, does this use nvidia kernel drivers or nouveau kernel drivers?), which are already mostly open source.
This would mean that you could run a full open source graphics stack on an ARM System on Chip (SoC). I don't know if this is possible on any current SoC out there.
Still, a great news