Date:   Fri, 24 Feb 2023 20:14:54 +0530
From:   Sunil V L <sunilvl@ventanamicro.com>
To:     Andrew Jones <ajones@ventanamicro.com>
Cc:     Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marc Zyngier <maz@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        linux-riscv@lists.infradead.org, linux-acpi@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Conor Dooley <conor.dooley@microchip.com>,
        Anup Patel <apatel@ventanamicro.com>,
        Atish Patra <atishp@rivosinc.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH V2 18/21] RISC-V: Add ACPI initialization in setup_arch()
Message-ID: <Y/jNZg5k1UZ26i1X@sunil-laptop>
References: <20230216182043.1946553-1-sunilvl@ventanamicro.com>
 <20230216182043.1946553-19-sunilvl@ventanamicro.com>
 <20230220200743.rev3djzbaa2jcmg6@orel>
 <Y/ivRjQbIna7M4R2@sunil-laptop>
 <20230224130712.c42ob66ux5xhffbm@orel>
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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