The sound subsystem updates for Linux 3.17 are mostly centered around a ton of ASoC updates, but there's also a few noteworthy changes to the commonly used HD Audio code. In particular, upcoming Intel Braswell hardware has its audio supported by the Linux 3.17 kernel. Going along with Braswell as HD Audio changes are fix-ups for several HD-Audio-using systems including the HP Envy TS, Dell XPS 15, and Gigabyte BXBT-2807, among other platforms.
Within the ASoC realm for Linux 3.17 are new drivers for the Cirrus Logic CS4265, Freescale i.MX ASRC, Realtek
RT286, Realtek RT5670, Rockchip RK3xxx I2S, and Texas Instruments TAS2552. the pull request.