Conditional for variable Drive <-> Chassis relationships?

Yes, and it's a simple "ReadRequirement" value - no conditionals necessary. A "ReadRequirement" of "Supported" indicates that the service has to show support (include) the property in at least one instance of the resource - but it doesn't have to appear in all instances. I don't believe the validator checks this case currently - because these cases could be very dependent on machine configuration.

For example, a property specific to NV-DIMMs may be supported by the implementation, and if an NV-DIMM is present in the system, the validator would pass it. But if no NV-DIMMs are installed, it would (incorrectly) fail it.

There are several ReadRequirement values that we can't test for (but they show up in generated documentation), so this isn't a unique case.

But I'll open an issue on the validator that we could check for this (it's not a simple test), and perhaps add a flag to determine how to handle these (fail or ignore/warn). Because the case you're trying to check is something that should pass regardless of configuration (even with all 'empty' drive resources).

Jeff