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Subject: Re: [External] [PATCH v2 1/3] riscv: obtain ACPI RSDP from FFI.
From:   Jessica Clarke <jrtc27@jrtc27.com>
In-Reply-To: <CANBLGcwcvK55dZ1__wvWCtcw=XoKt=qki8g6C_QYo+TBqqJ=TA@mail.gmail.com>
Date:   Mon, 3 Jul 2023 22:32:53 +0100
Cc:     =?utf-8?B?6L+Q6L6J5bSU?= <cuiyunhui@bytedance.com>,
        Andrew Jones <ajones@ventanamicro.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        rminnich@gmail.com, Mark Rutland <mark.rutland@arm.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>, jdelvare@suse.com,
        yc.hung@mediatek.com, angelogioacchino.delregno@collabora.com,
        allen-kh.cheng@mediatek.com, pierre-louis.bossart@linux.intel.com,
        tinghan.shen@mediatek.com,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-acpi@vger.kernel.org, geshijian@bytedance.com,
        weidong.wd@bytedance.com
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References: <20230702095735.860-1-cuiyunhui@bytedance.com>
 <20230703-71f67eb66a037f5c0fb825c6@orel>
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To:     Emil Renner Berthing <emil.renner.berthing@gmail.com>
Precedence: bulk

On 3 Jul 2023, at 19:58, Emil Renner Berthing =
<emil.renner.berthing@gmail.com> wrote:
>=20
> On Mon, 3 Jul 2023 at 15:33, =E8=BF=90=E8=BE=89=E5=B4=94 =
<cuiyunhui@bytedance.com> wrote:
>>=20
>> Hi drew,
>>=20
>> On Mon, Jul 3, 2023 at 9:01=E2=80=AFPM Andrew Jones =
<ajones@ventanamicro.com> wrote:
>>>=20
>>>=20
>>> (This is a reply to a non-existent cover letter.)
>>=20
>> This has been discussed many times with Ard, Please refer to :
>> =
https://patches.linaro.org/project/linux-acpi/patch/20230426034001.16-1-cu=
iyunhui@bytedance.com/
>=20
> Hi Yunhui,
>=20
> =46rom that discussion it was mentioned that that arm supports 3 =
methods
> of booting:
>  direct + devicetree
>  EFI + devicetree
>  EFI + ACPI
> ..but not
>  direct + ACPI
>=20
> To me it isn't obvious from that or this thread, and since arm seems
> to be doing fine without the 4th option I'm curious why that's
> necessary on riscv?

If anything we should be removing option 1, because that=E2=80=99s not a
cross-OS standard (though RISC-V=E2=80=99s SBI direct booting is at =
least not
tied to the OS). Any application-class platform spec is going to
mandate EFI, because, whatever your thoughts of EFI are, that is *the*
standard. And if you=E2=80=99re willing to pick up all the complexity of =
ACPI,
what=E2=80=99s a bit of EFI (especially if you only go for a minimal one =
a la
U-Boot)?

Jess

>>> I'm not a big fan of adding yet another interface. Have you =
considered
>>> doing something like [1]?
>>>=20
>>> [1] =
https://github.com/tianocore/tianocore.github.io/wiki/UefiPayloadPkg
>=20
> Also you didn't answer this question, which I'd also like to hear a =
reply to.
>=20
> /Emil
>=20
>>> Thanks,
>>> drew
>>=20
>> Thanks,
>> Yunhui
>>=20
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>=20
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
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