[External] Re: [PATCH v2 1/3] riscv: obtain ACPI RSDP from FFI.

[运辉崔]

Hi Sunil,

On Mon, Jul 3, 2023 at 12:22 PM Sunil V L <sunilvl at ventanamicro.com> wrote:
>
> Hi Yunhui Cui,
> On Sun, Jul 02, 2023 at 02:47:41PM +0100, Conor Dooley wrote:
> > Hey,
> > %subject: riscv: obtain ACPI RSDP from FFI.
> >
> > This subject is a bit unhelpful because FFI would commonly mean "foreign
> > function interface" & you have not yet introduced it. It seems like it
> > would be better to do s/FFI/devicetree/ or similar.
> > Please also drop the full stop from the commit messages ;)
> >
> > Please use a cover letter for multi-patch series & include changelogs.
> >
> > +CC Sunil, Alex:
> >
> > Can you guys please take a look at this & see if it is something that we
> > want to do (ACPI without EFI)?
> >
>
> We have supported ACPI only with UEFI. The current booting contract
> between firmware and OS is to pass only one of DT or ACPI, not both.
> This approach brings another booting contract for Linux mixing ACPI and
> DT which affects RVI specs. As per policy and since it can affect
> multiple OSs, a frozen RVI spec is required for taking this patch into
> linux. So, could you please bring this topic for discussion in [1] and
> get agreement?
>
> Isn't it simpler to provide a minimum UEFI configuration table and
> stubbed BS/RS?
>
> Have you done a PoC? I am curious how do you handle EFI memory map
> dependencies.

Yes, Poc has been completed.
a memory node in DTS can solve it.

>
> In case this is approved, I am wondering why do we need new FFI?
>
> [1] - https://lists.riscv.org/g/tech-brs

We have discussed with Ard and Ron many times about the series of
questions you mentioned above, and reached a consensus.
Please see the v1:
https://patches.linaro.org/project/linux-acpi/patch/20230426034001.16-1-cuiyunhui@bytedance.com/

Thanks,
Yunhui