The "host1x" is found with NVIDIA Tegra SoCs and this new patch-set by NVIDIA's Arto Merilainen allows accessing the host1x hardware from user-space. There's already been 2D acceleration for NVIDIA Tegra hardware that's been done using host1x. The new patches on Friday are in their second revised form.
The NVIDIA Tegra Stream library is for libdrm and provides interfaces for buffer management, command stream construction, and work synchronization for user-space submitting to the NVIDIA Tegra DRM kernel driver. The kernel-side patches for improving the Tegra DRM will hopefully work their way into the Linux 3.10 kernel.
The new patches this morning can be found on the dri-devel list.
Nice job, NVIDIA, on this direct code contribution. The other big milestone that happened last week was initial open-source 3D support for Tegra.