Mesa Git Makes It Easier Activating Rusticl OpenCL Device Support

The very promising Rusticl Rust-based OpenCL implementation within Mesa has landed a set of patches today that make it easier to enable the OpenCL compute device support with the various Gallium3D drivers.

Since being merged back in September, Rusticl has been advancing rapidly and is performing great and beginning to work with more of the Gallium3D drivers -- even Zink too for getting it atop Vulkan drivers. But given its still early, experimental state, it's not being activated by default quite yet and as some Gallium3D drivers have issues to address or improvements to make before it will be really ready for all end-users.

Merged today into Mesa 22.3-devel is support for the RUSTICL_ENABLE= environment variable. This can be used for setting the driver name of enabling and optionally even appending the index ID of the device / GPU you want to enable for multi-GPU systems. With setting say RUSTICL_ENABLE=iris would enable Rusticl for the Intel Iris Gallium3D driver or RUSTICL_ENABLE=radeonsi for the RadeonSI Gallium3D driver. Thus until Rusticl is in good enough shape to enable by default everywhere, this RUSTICL_ENABLE knob should be useful for those developers and testers of this OpenCL 3.0 implementation.

Today's commit activity also adds RUSTICL_DEVICE_TYPE if instead of specifying the GPU OpenCL device type it could alternatively be set to accelerator, CPU, or custom. Another testing knob added is RUSTICL_CL_VERSION= as an environment variable if wanting to override the advertised OpenCL version for all devices.

See this merge request if interested in more details on these new Rusticl knobs.