AMD had been releasing documentation for their Radeon GPUs, as well as supporting development of the open source radeon driver for linux (http://www.x.org/wiki/

AMD had been releasing documentation for their Radeon GPUs, as well as supporting development of the open source radeon driver for linux (http://www.x.org/wiki/radeon/ http://www.x.org/wiki/radeon/ and http://www.x.org/docs/AMD/ http://www.x.org/docs/AMD/). The open source driver just has nowhere near the resources devoted to it that the proprietary drivers have.