Re: [PATCH V3 18/20] RISC-V: Add ACPI initialization in setup_arch()

Conor Dooley
2023-03-08T10:21:20Z

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On Wed, Mar 08, 2023 at 03:12:18PM +0530, Sunil V L wrote:
> On Mon, Mar 06, 2023 at 09:17:34PM +0000, Conor Dooley wrote:
> > On Fri, Mar 03, 2023 at 07:06:45PM +0530, Sunil V L wrote:
> > > Initialize the ACPI core for RISC-V during boot.
> > >
> > > ACPI tables and interpreter are initialized based on
> > > the information passed from the firmware and the value of
> > > the kernel parameter 'acpi'.
> > >
> > > With ACPI support added for RISC-V, the kernel parameter 'acpi'
> > > is also supported on RISC-V. Hence, update the documentation.
> > >
> > > Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> > > Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > > Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> > > ---
> >
> > > +static int __init acpi_fadt_sanity_check(void)
> > > +{
> > > + struct acpi_table_header *table;
> > > + struct acpi_table_fadt *fadt;
> > > + acpi_status status;
> > > + int ret = 0;
> > > +
> > > + /*
> > > + * FADT is required on riscv; retrieve it to check its presence
> > > + * and carry out revision and ACPI HW reduced compliancy tests
> > > + */
> > > + status = acpi_get_table(ACPI_SIG_FADT, 0, &table);
> > > + if (ACPI_FAILURE(status)) {
> > > + const char *msg = acpi_format_exception(status);
> > > +
> > > + pr_err("Failed to get FADT table, %s\n", msg);
> > > + return -ENODEV;
> > > + }
> > > +
> > > + fadt = (struct acpi_table_fadt *)table;
> > > +
> > > + /*
> > > + * Revision in table header is the FADT Major revision, and there
> > > + * is a minor revision of FADT.
> >
> > What is the point of this part of the comment? Isn't it obvious from the
> > below code that you expect a major and minor revision?
> > If feel like you're trying to make a point in it, but the point has been
> > lost :/
> >
> It just highlights that major and minor revision fields are in two
> different places.

I thought that that was what you meant, but only because the code does
it. The comment doesn't actually say so!

Instead of deleting it, something like the following?
/*
* The revision in the table header is the FADT's Major revision. The
* FADT also has a minor revision, which is stored in the FADT itself.
* <snip>

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