According to a statement by AMD/ATI:

We've always supported open source, and for relevant markets such as
servers, we release open source drivers so that companies such as Red Hat
can include them in their distros.

[...]

However, for other markets, such as workstation and consumer, performance
and feature differentiation are key metrics. Proprietary, patented
optimizations are part of the value we provide to our customers and we have
no plans to release these drivers to open source.

[...]

In addition, multimedia elements such as content protection must not, by
their very nature, be allowed to go open source.

This makes one wonder. AMD has also, like Intel, always publicized their specifications and programming manuals for their processors and chipsets.

In related news Intel asked to be able to serve a subpoena (a legal writ which calls you to attend and function as a witness in a judicial proceeding under a penalty in case of disobedience) on ATI in the anti-trust case versus AMD.

With recent news of AMD acquiring ATI there was some incorrect reporting that AMD would be dropping the ATI brand in favour of tacking Radeon on its own brand name of AMD. According to Ars Technica the name drop was a miscommunication that spread like fire through the blogosphere as well as online news. This is both the advantage and disadvantage of the quick turn-around time of the online media. One would think that serious technical journalists, however, would verify this with AMD and/or ATI themselves before reporting.

In related news Intel revealed a website where they are offering source code for their 965 IGP. And it becomes even more interesting when put into perspective with an article from InfoWorld where it is said that AMD is strongly considering releasing open source at least a part of the ATI graphics drivers. One can only wonder how NVIDIA will react to these developments.