Besides the Intel DRM kernel driver support for Intel's next-generation Broadwell "Gen8" graphics cores that succeed Haswell in the 2014 CPUs, there's also been a Broadwell Mesa Git branch that has yet to be merged to master.
In the middle of November, there was libdrm support for Intel Broadwell. With the DRM library prerequisite addressed for the next-generation Intel graphics, Chris Wilson committed today the initial Broadwell X.Org driver support with an SNA acceleration back-end.
In the commit message for supplying the Broadwell SNA 2D accelerated back-end, Chris noted that it shouild match in functionality to earlier hardware, but the hardware acceleration code has yet to be tuned for the new micro-architecture.
In another commit pushed at the same time, the Broadwell hardware for now is just being reported as "Gen8" hardware until Intel officially announces their graphics naming scheme for the Broadwell processors.
Broadwell will be very exciting when the processors launch within the next few months. The processor and graphics performance should both be great and once again there will be launch-day open-source Linux graphics support. Benchmarks of Intel Broadwell on Linux will also be found on Phoronix.