Radeon R600 Gallium3D Flips On OpenGL 4.5 For NIR Backend

The experimental NIR back-end for the R600 Gallium3D driver as an alternative to the default TGSI code-path has now enabled OpenGL 4.5 support for capable GPUs.

With a number of OpenGL 4.5 conformance test suite fixes that were merged on Tuesday, OpenGL 4.5 is now ultimately enabled for the NIR code path.

This OpenGL 4.5 support is enabled for all Radeon HD 5000 "Cedar" GPUs through the Radeon HD 6000 series where the R600g driver support ends. Previously and for the non-NIR code-path this is at OpenGL 4.3 support.

The enabling for OpenGL 4.5 with NIR is exciting but keep in mind the Radeon HD 5000 series is already a decade old and the usefulness will be limited in many cases. If you are engaging in any serious workloads, chances are you would be much better off upgrading to anything newer in the AMD GCN family for better performance, Vulkan support, and being on an actively maintained driver stack.

In any case it's been great seeing what Gert Wollny has been able to accomplish with NIR for R600g. It was just a few months ago that Gert was able to get compute shaders working for R600g NIR. It was just last year as well that the initial R600g NIR back-end was merged with a focus on the Radeon HD 5000/6000 series.

Trying out R600g NIR is possible with the R600_DEBUG=nir environment variable on the latest versions of Mesa - but ideally Mesa 21.1-devel for the best experience.