I'm not sure what a 'shim driver' is, though. If someone creates a new closed-source DDX for radeon that
interacts with the existing libdrm kernel implementation - would that be a 'shim driver'?
If so, how would the kernel devs be able to reject them? It's userspace like the mesa bits.
And they surely had to stick to the kernel drm part if there is at least one OSS userspace driver that needs it, right?