If only those drivers were backed up seriously by their corresponding hw manufacturers, maybe Valve would consider trusting them a bit more. If Valve source code is spotted in the wilde, there will be only that many possible leaks, and all of them would be dependable (i.e. able to pay up in case of successful litigation). With independant teams of developers, it is very understandable that Valve doesn't want to take that risk. The only thing that Valve might do is contribute enginering strength to those other drivers projects, but I suspect that Valve doesn't have the workforce for that. Besides, that wouldn't necessary be seen as a keen move from Intel's perspective. I'm all for more open source drivers, but really it has to come from the manufacturers first and foremost, in this case at least. The only case I know of a game shop working directly on an OSS driver was when John Carmack helped with the Utah GLX driver effort, and that was a long time ago.