A week ago I mentioned the classic R300/R600 drivers were on their deathbed as Mesa developers wanted to get rid of these legacy DRI1-only drivers in order to provide for a cleaner Mesa code-base and allow for improvements to be made easier as the open-source developers work towards OpenGL 3.0 (and eventually OpenGL 4.0) compliance.
With most developers agreeing with killing these classic open-source Radeon drivers, the action was carried out this afternoon by Intel's Eric Anholt.
Besides removing the R300 and R600 DRI drivers themselves, also stripped away from mainline Mesa is also several components that are no longer needed, including the classic R300 shader compiler, the non-libdrm kernel memory manager support, remaining DRI1 bits (e.g. DRI1 vblank), the legacy buffer object manager code, etc. The non-kernel-memory-manager and DRI1 code from the ATI R200 classic Mesa driver has also been killed. Deleting this code shortens up the Mesa code-base by about 80,000 lines.
Most users will be directly unaffected by this change since the Gallium3D versions of the R300 and R600 drivers have been the recommended components for some time now. The Gallium3D drivers offer a much cleaner architecture, are normally much faster, and offer a greater feature-set than these classic drivers. The only group of individuals that may be really affected is BSD and Solaris users due to their poor graphics situation and generally lacking the kernel memory management, DRI2, and KMS components.