The problem is that mesa's "Clover" OpenCL driver currently only supports OpenCL 1.1 and does not support OpenCL images and was abandoned for years. This makes

The problem is that mesa's "Clover" OpenCL driver currently only supports OpenCL 1.1 and does not support OpenCL images and was abandoned for years. This makes it more or less useless. Additionally, these code paths are not very well tested or optimized. This has been in the works recently though, I've seen PRs for OpenCL 3.0 and OpenCL Image, not sure if they're in yet. With both Redhat and Microsoft being interested in working on this area now, I expect to see improvements soon.