Mesa 22.2 RADV Driver Adds Vulkan Ray-Tracing Maintenance Extension

As added reason for Radeon Linux users to celebrate today beyond Blender 3.2 releasing with AMD HIP Linux render support is that Mesa's Radeon Vulkan driver "RADV" continues maturing with its ray-tracing support.

The RADV ray-tracing support continues steadily improving albeit is still rather experimental in nature. Last month saw RADV enabling ray queries by default as well making other strides.

Today the milestone crossed is RADV supporting VK_KHR_ray_tracing_maintenance1. The VK_KHR_ray_tracing_maintenance1 extension was added in Vulkan 1.3.213 one month ago with various minor ray-tracing specification updates. The VK_KHR_ray_tracing_maintenance1 changes are all small that alone do not warrant their own extensions or revisions to the spec but together at least are enough to warrant this "maintenance1" update for Vulkan ray-tracing.

VK_KHR_ray_tracing_maintenance1 adds support for the SPIR-V KHR_ray_cull_mask extension to provide access to the built-in cull mask shader variable, support for a new pipeline stage and access mask built on VK_KHR_synchronization2, new acceleration structure query parameters, and an optional new indirect ray-tracing dispatch command. See the Vulkan spec for more details on the KHR_ray_tracing_maintenance1 changes.

This merge by Konstantin Seurer hit Mesa 22.2-devel today for implementing the necessary changes with more than one thousand lines of new code. Kudos to Konstantin Seurer who continues working on much of the RADV ray-tracing support along with the usual RADV developers.