Intel's Ironlake hardware may be very old and not nearly as nice as the latest generation Haswell
parts, but shipped today was a new patch-set for implementing hardware context support.
Hardware context support
is needed for OpenGL transform feedback with geometry shaders by providing a way for the graphics core to save and restore state between batch buffer boundaries.
Patches for the older Ironlake IGPs have come about before, but never merged. Sunday's set of nine patches also finally re-enables RC6 power-savings support for Ironlake.
The set of patches, which could be merged for the Linux 3.12 kernel at the earliest, can be found on the intel-gfx list