Re: [edk2-platforms PATCH 2/7] Marvell: Armada7k8k/OcteonTx: Add missing _STA methods in ACPI tables


Ard Biesheuvel
 

On Tue, 10 Aug 2021 at 16:36, Samer El-Haj-Mahmoud
<samer.el-haj-mahmoud@...> wrote:

Apologies for the tardiness in replying to this. Please see my comments below.

-----Original Message-----
From: Marcin Wojtas <mw@...>
Sent: Friday, July 30, 2021 5:57 AM
To: Ard Biesheuvel <ardb@...>
Cc: Samer El-Haj-Mahmoud <Samer.El-Haj-Mahmoud@...>; edk2-
devel-groups-io <devel@edk2.groups.io>; Leif Lindholm
<leif@...>; Ard Biesheuvel <ardb+tianocore@...>;
Grzegorz Jaszczyk <jaz@...>; Grzegorz Bernacki
<gjb@...>; upstream@...; Jon (jon@...)
<jon@...>
Subject: Re: [edk2-platforms PATCH 2/7] Marvell: Armada7k8k/OcteonTx:
Add missing _STA methods in ACPI tables

Hi Ard,

czw., 29 lip 2021 o 11:58 Ard Biesheuvel <ardb@...> napisał(a):

On Thu, 29 Jul 2021 at 11:46, Marcin Wojtas <mw@...> wrote:

Hi Ard,

pon., 19 lip 2021 o 17:06 Marcin Wojtas <mw@...> napisał(a):

Hi Ard,

pon., 19 lip 2021 o 11:54 Ard Biesheuvel <ardb@...> napisał(a):

On Mon, 19 Jul 2021 at 11:31, Marcin Wojtas <mw@...>
wrote:

BBR 1.0 spec says that _STA is required for each device in DSDT or
SSDT.
Fix that for all platforms with the Marvell SoC's.
Can we fix the BBR instead? If ACPI itself does not require _STA, BBR
should not require it either.

I consulted with ARM on the matter. SBBR has requirements of things
that are otherwise optional in UEFI/ACPI/SMBIOS. Also some OS's may
require that and I can see those methods in most of the other ACPI
source files in the edk2-platfoms tree. I think the BBR requirements
discussions can follow, but it would be great if this change can be
applied, so that no to block other development.
Do you have any feedback to the patchset and the _STA methods
concerns?
Yes. I would like to understand why _STA methods are now mandated by
BBR.
Understood. Providing an answer may not be immediate and may possibly
require further discussion on the SystemArchAC level.
How about we withdraw this single patch for now and process the
remaining ones? We would come back to the _STA subject, as soon as
there's more information available.

Best regards,
Marcin
_STA has been required in SBBR since ver 1.0 (published 2016, with the 0.9 draft since 2014)
https://developer.arm.com/documentation/den0044/b/?lang=en

I do not have the history on why SBBR 1.0+ requires _STA, but it most likely has to do wit the Windows strong use case for it: https://docs.microsoft.com/en-us/windows-hardware/drivers/bringup/device-management-namespace-objects#device-status-changes . Windows is a key OS targeted by SBBR.
OK, I stand corrected again :-)

Marcin,

I won't object further to these additions -please respin the patch on
top of current edk2-platform and I will apply it right away.

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