R600g Driver Patched For OpenGL 4.0 Indirect Draw Support
The OpenGL 4.0 GL_ARB_draw_indirect extension is already supported by the RadeonSI Gallium3D driver for Radeon HD 7000 series and newer (along with Intel's driver, Nouveau NVC0, LLVMpipe, and Softpipe) while now it's coming to R600g. Besides needing a patched R600g driver for GL_ARB_draw_indirect support, there's a related kernel patch that has yet to be applied and thus won't land until at least the Linux 3.19 kernel. Assuming you have a patched software stack, you need a Radeon HD 5000 series or newer GPU to benefit from this OpenGL 4.0 extension.
There's the Mesa patch and a kernel patch for the Radeon DRM code. These patches were posted on Saturday by Glenn Kennard. Those unfamiliar with the GL_ARB_draw_indirect extension can find it documented at OpenGL.org. Given that there's kernel changes needed that won't land until at least the next cycle (Linux 3.19), the R600g support likely won't be merged ahead of the Mesa 10.4 branching that's set to take place next week.