Re: [Linaro-acpi] [PATCH v7 04/17] ARM64 / ACPI: Introduce early_param for "acpi" and pass acpi=force to enable ACPI

Ard Biesheuvel
2015-01-30T15:12:15Z

On 30 January 2015 at 14:48, Timur Tabi <timur@codeaurora.org> wrote:
> Catalin Marinas wrote:
>>
>> Anyway, rather than a "I-created-an-empty-dtb" property, I would
>> actually say something like "dtb-contains-no-hardware-description".
>
>
> Why do we need a property for this? Wouldn't the absence of a hardware
> description be the best way to see if the dtb contains no hardware
> description? It's like putting a sign on an empty bookshelf that says,
> "there are no books here."
>

So what constitutes a 'hardware description'? A /cpu node? A memory node?
I don't think there is a mandated minimal set of nodes, even if
booting without cpu and memory nodes doesn't get you very far.

So those should go hand in hand: if we are going to implement logic
that decides a DTB is considered empty if it has no /cpu node, we
should update the boot protocol to mandate the presence of a /cpu node
for DT boot, and not change the rules every couple of months if
someone's use case requires it.

--
Ard.