AMD Instinct MI300 "GFX940" Support Merged To Mesa 23.1

While going back a year there has been "GFX940" open-source driver work happening within the AMDGPU LLVM compiler back-end and AMDGPU/AMDKFD Linux kernel drivers and the like, only this week was support merged for GFX940 into Mesa.

GFX940 is the latest AMD CDNA evolution for what is the AMD Instinct MI300 accelerator. With this being a headless accelerator, the Mesa support for OpenGL and Vulkan isn't all that interesting nor a primary focus with it primarily for use with AMD's ROCm compute stack. However, the Mesa support does have some weight primarily for the video/image acceleration support. If wanting to carry out any GPU-based video acceleration with the Instinct accelerator, with the RadeonSI Gallium3D driver is then the video acceleration state tracker for VA-API.

This week's Mesa merge to Mesa 23.1 adds the GFX940 chip as well as enabling the video acceleration support. The video capabilities with the Instinct MI300 appear to be similar to that of GFX11/RDNA3 hardware.

Adding the GFX940 support to Mesa was just over four thousand lines of new code, most of which were +3k lines for a JSON-basd register file. For the most part though the GFX940 is following existing GFX9 (CDNA) code paths or VCN video acceleration paths of GFX11 (RDNA3). This Mesa work is just around GFX940 while in kernel space recently there has been work around a newer GFX943 variant. In any event, this AMD GFX940 support has now landed in time for Mesa 23.1 with its feature freeze soon and stable release out later this quarter.