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

Sunil V L
2023-02-24T14:45:22Z

On Fri, Feb 24, 2023 at 02:07:12PM +0100, Andrew Jones wrote:
> 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.
>
Okay Let me add the current FADT version of 6.5 which for sure
supports HW_REDUCED flag. When the spec gets released, we can update with
actual revision we need for RISC-V.

Thanks,
Sunil