Over the coming weeks, we will produce a detailed reference design for ACPI on #ARM v8. All of the major Server SoC designs in progress for ARMv8 use ACPI but are largely NDA at this stage. Some will upstream with DT because I have pushed vendors to upstream drivers over and above fighting the ACPI flamewars as a gate to upstream. But we will make sure everything is migrated over as quickly as possible. To support this necessary activity, there is a need for a reference to show folks how it should be done (in public, rather than the many private sessions we have on design reviews) and this will happen (there is a cunning plan). We cannot rely on the Intel style "just build it like the last time" approach to server platforms, and it is time to have more rigorous references that build upon the platform standards in the works. There are many ways to do it (most bounce through an on-chip SCP/BCM via AML for e.g. clock and power state transitions), but fewer ways to do it right. Either way, I do not intend to get into a "should we do ACPI" discussion, only how to do it.