Re: [PATCH v4 2/3] hw/acpi: add indication for i8042 in IA-PC boot flags of the FADT table

[Igor Mammedov <imammedo@redhat.com>]

On Tue, 1 Mar 2022 15:22:17 +0530 (IST)
Ani Sinha <ani@anisinha.ca> wrote:

> On Tue, 1 Mar 2022, Igor Mammedov wrote:
> 
> > On Mon, 28 Feb 2022 22:17:32 +0200
> > Liav Albani <liavalb@gmail.com> wrote:
> >  
> > > This can allow the guest OS to determine more easily if i8042 controller
> > > is present in the system or not, so it doesn't need to do probing of the
> > > controller, but just initialize it immediately, before enumerating the
> > > ACPI AML namespace.
> > >
> > > This change only applies to the x86/q35 machine type, as it uses FACP
> > > ACPI table with revision higher than 1, which should implement at least
> > > ACPI 2.0 features within the table, hence it can also set the IA-PC boot
> > > flags register according to the ACPI 2.0 specification.
> > >
> > > Signed-off-by: Liav Albani <liavalb@gmail.com>
> > > ---
> > >  hw/acpi/aml-build.c         | 11 ++++++++++-
> > >  hw/i386/acpi-build.c        |  9 +++++++++
> > >  hw/i386/acpi-microvm.c      |  9 +++++++++  
> > commit message says it's q35 specific, so wy it touched microvm anc piix4?  
> 
> Igor is correct. Although I see that currently there are no 8042 devices
> for microvms, maybe we should be conservative and add the code to detect
> the device anyway. In that case, the change could affect microvms too when
> such devices get added in the future.

when that case actually arises implement it then, so I'd say don't generalize
that unless it's actually used within series.
Or planned to be used in near future in which case commit message should
mention that.

> 
> echo -e "info qtree\r\nquit\r\n" | ./qemu-system-x86_64 -machine microvm
> -monitor stdio 2>/dev/null | grep 8042
> 
> <empty>
>