Re: [PATCH V2 18/21] RISC-V: Add ACPI initialization in setup_arch()

Andrew Jones
2023-02-24T13:07:19Z

On Fri, Feb 24, 2023 at 06:06:22PM +0530, Sunil V L wrote:
> On Mon, Feb 20, 2023 at 09:07:43PM +0100, Andrew Jones wrote:
> > On Thu, Feb 16, 2023 at 11:50:40PM +0530, Sunil V L wrote:
...
> > > + fadt = (struct acpi_table_fadt *)table;
> > > +
> > > + if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
> >
> > Do we also need to check for ACPI version 5.0+ when checking for HW
> > reduced?
> >
> We need to add version check of FADT once spec is released. Will
> update it at that time.
>

I was thinking we need the version check already just for the flag.
The spec has a footnote that says

"The description of HW_REDUCED_ACPI provided here applies to ACPI
specifications 5.0 and later"

It doesn't really matter in practice since no RISC-V machines can
boot with ACPI less than a version that support the new RISC-V
tables... But I'd rather we either document that fact, or just do
the check.

Thanks,
drew