It seems that Valve has just launched a new Linux blog where a brand new team at Valve is working on bringing Steam and the Source engine to the Linux platform.
For some time, Gabe Newell has been interested in the possibility of moving Steam and the Source game engine to Linux. At the time, Valve was already using Linux by supporting Linux-based servers for Source-based games and also by maintaining several internal servers (running a 64-bit version of Ubuntu server) for various projects.
In 2011, based on the success of those efforts and conversations in the hallway, they decided to take the next step and form a new team. At that time, the team only consisted of a few people whose main purpose was investigating the possibility of moving the Steam client and Left 4 Dead 2 over to Ubuntu. The goal is to have L4D2 performing under Linux as well as it performs under Windows.
The focus for the team at the moment is:
- getting the Steam client onto Linux with full functionality
- optimizing a version of L4D2 running at a high frame rate with OpenGL
- porting additional Valve titles
You can find more information and the Linux blog posts over here.