Nowadays multiple ARM-based devboards provide ACPI, so this restriction is not a good option anymore. For example I've used standard Buildroot acpi package on Cubieboard 6 without any issue.
Sorry, what firmware provides ACPI on your cubieboard? Or do you just mean that some of the functionality of acpid is usable without firmware/kernel support? drivers/acpi in the Linux kernel is guarded by ARCH_SUPPORTS_ACPI, which is selected for arm64/ia64/x86. With that said, if it builds on other architectures and there are use cases for it on those, then I don't have a problem exposing it.
Hi, Peter! I'm not a specialist in ACPI or power management, so please don't blame me a lot :) It seems to me, that you are right. All ACPI-related options in Cubieboard 6 kernel config are disabled (it's ARM, not ARM64). But at the same time, acpid handles power button pushes and powers off the board. If no acpid is running, I can only reboot the board by long push. So, it's useful. I found no building issues.
Fixed by https://git.buildroot.org/buildroot/commit/?h=next&id=1bcc6e87410c76efb2f4bdd9714916acef84b7d0. Thanks!