On 12/11/2014 15:10, Mark Rutland wrote:
We can't just pick-and-mix portions of ACPI and state that it's specified and standard.
But that's what you already do if you want to build ACPI tables from DT. You are already picking-and-mixing the variable portions of the ACPI tables and make a DT bindings for them.
I don't follow. I argued _against_ trying to build ACPI tables from DT because the two don't quite match up anyway. I argued _against_ trying to convert ACPI tables to DT in prior discussions for similar reasons.
Sorry, that was not you-Mark, but more you-ARM.
And in fact I'd tend to agree with you, but if there are people that want not to use ACPI or UEFI or both, I think it's better if the UEFI firmware swallows the same pill and builds ACPI from DT.
In addition to fixing up the other specs which are affected by this (e.g. how we describe those additional CPUs). There's also some de-ACPIing to be done in addition to de-x86ification, and we need to be careful to ensure we have access to all the information we require in the absence of ACPI, and that we have a well defined behaviour on both sides of the interface for what would previously have been implicit in ACPI.
Yes, I agree. On the QEMU side the de-ACPIfication would have to be done anyway (no GPE because of the reduced hardware), but you need extra de-ACPIfication for stuff like the SRAT.
I'm not saying that this is impossible. It's just a greater body of work than modifying one spec.
No doubt about that.
Paolo