[igt-dev] [RFC PATCH 1/1] drm/i915: Never allow userptr into the new mapping types

[Chris Wilson]

Quoting Janusz Krzysztofik (2020-01-31 13:20:37)
> Commit 4f2a572eda67 ("drm/i915/userptr: Never allow userptr into the
> mappable GGTT") made I915_GEM_MMAP_GTT IOCTLs to fail when atepmted
> on a userptr object in order to protect from a lockdep splat.  Later
> on, new mapping types were introduced by commit cc662126b413
> ("drm/i915: Introduce DRM_I915_GEM_MMAP_OFFSET").  Those new mapping
> types suffer from the same lockdep splat issue but they now succeed
> when tried on top of a userptr object.  Fix it.
> 
> While being at it, return -EINVAL which seems to better reflect the
> reason for the failure than -ENODEV.

No. It is not a user error, it's a failure to implement support for it,
so we parcel it off as an incompatible device.
-Chris