@Sobex @SharpLimefox It's possible in some cases, not others. You can't avoid the subsystems "above" you providing your services (DRM for me) and "below" you interacting with other devices, but you can avoid "helper" subsystems and parts of them.

The DRM scheduler is a helper. The other thing I'm going to RiiR is the GPU page table management, which is currently using the IOMMU page table helpers (both because the maintainer stopped replying to my emails... and because since the original submission my needs have diverged enough from the standard code that I think it stopped making sense to reuse it and try to fight to shoehorn those features in).