Valve has released a couple of days ago, December 19, a new build of its SteamOS gaming Linux operating system based on Debian GNU/Linux, bringing updated Intel drivers as well as many other interesting features that were missing from the initial build of the distro.
Therefore, we can report that SteamOS 1.0 Beta Build 12.19.2013 updates the Intel graphics stack to the recently released Mesa 10.0.1, re-enables Intel KMS support by applying a fix in the kernel, enables 3D passthrough in the VMWare driver, adds support for NTP time, and adds XDG directory helpers.
The new build of SteamOS also fixes the firmware upgrade process for the Steam controller by adding USB auto-mounting. It displays some text feedback when building the Linux kernel drivers during the first boot, enables audio from the desktop session, and fixes some audio issues with Trine 2.
You can download SteamOS 1.0 Beta Build 12.19.2013 right now from Softpedia.