Suppose your shader only uses some subset of the binding slots specified by the root signature (as known at shader compile time). When you bind specific resources with SetGraphicsRootDescriptorTable(), some of the descriptors in the descriptor heap are therefore unused. What exactly must those unused descriptors be for correct behavior across all tier 1-2 hardware?
Must unused descriptors be null, or may they refer to actual resources (possibly used ones bound at the same time)? Are there additional undocumented "some hardware" crashes, beyond texture dimension mismatches?
To highlight the ambiguity, this is everything I could dig up: