Nouveau Gets Patches For OpenGL AZDO ARB_shader_ballot

Following the work laid by AMD developers on wiring ARB_shader_ballot into RadeonSI, a student developer working on Nouveau has posted support for this OpenGL extension.

ARB_shader_ballot can be used by OpenGL app/game developers as one of the extensions for "approaching zero driver overhead" techniques (AZDO) and is in part why RadeonSI developers were recently working on that and ARB_sparse_buffer for their RadeonSI Gallium3D driver.

Boyan Ding has now posted nine patches amounting to just less than 300 lines of code for getting ARB_shader_ballot implemented for Kepler GPUs and newer. ARB_shader_ballot allows some basic cross-invocation communication.

The patches for now are found on Mesa-dev. Also, kudos to Boyan Ding as being a student developer that's been among the community members working on Nouveau Gallium3D. His previous patch work was enabling the GLSL/TGSI on-disk shader cache in Nouveau.