Re: [PATCH 1/1] tools/libacpi: clear ASL warning about PCI0

["Ariel Otilibili-Anieli" <Ariel.Otilibili-Anieli@xxxxxxxxxx>]

On Monday, December 16, 2024 10:53 CET, Jan Beulich <jbeulich@xxxxxxxx> wrote:

> On 15.12.2024 16:40, Ariel Otilibili wrote:
> > * iasl complains _HID and _ADR cannot be used at the same time
> > 
> > ```
> > /usr/bin/iasl -vs -p tools/firmware/hvmloader/dsdt_anycpu.tmp -tc 
> > tools/firmware/hvmloader/dsdt_anycpu.asl 2>&1 | grep -B10 HID
> > tools/firmware/hvmloader/dsdt_anycpu.asl     40:        Device (PCI0)
> > Warning  3073 -                                    Multiple types ^  
> > (Device object requires either a _HID or _ADR, but not both)
> > ```
> > 
> > * generally _HID devices are enumerated and have their drivers loaded by 
> > ACPI
> > * this is from "ASL 2.0 Introduction and Overview" (page 4).
> > * removing _ADR, the warning is cleared out.
> 
> Okay, that's the positive aspect. Yet what about the potential fallout 
> thereof?
> Can you confirm that there's no risk of regressions with older guest OSes, for
> example?

Hi Jan,

OSes that were released after ACPI 2.0 should work [1]; including WinXP: 
The 2.0 specs says either _HID or _ADR should be included [2], not both 
(Section 6.1, page 146).

I chose WinXP because, on another patch, it came up in the discussion [3].

Ariel

[1] https://uefi.org/acpi/specs
[2] https://uefi.org/sites/default/files/resources/ACPI_2.pdf
[3] https://lore.kernel.org/all/ed248424-00a2-44ab-a7cf-3f2197d589a1@xxxxxxxxxx/
> 
> Jan