Re: [Qemu-devel] [PATCH v3 1/5] hw/i386: allow SHPC for Q35 machine

[Marcel Apfelbaum]

On 03/08/2017 15:52, Michael S. Tsirkin wrote:
> On Sat, Jul 29, 2017 at 02:37:49AM +0300, Aleksandr Bezzubikov wrote:
> > Unmask previously masked SHPC feature in _OSC method.
> >
> > Signed-off-by: Aleksandr Bezzubikov <address@hidden>

Hi Michael,


> This does not do what the subject says - it enables
> SHPC unconditionally. And I think it will actually break
> ACPI hotplug for the PC unless we add an interface to
> disable ACPI hotplug and enable SHPC.
>
> Pls limit to Q35 only.

The code is inside build_q35_osc_method,
I don't understand how it affects the PC machine.

Thanks,
Marcel


> > ---
> >   hw/i386/acpi-build.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> > index 6b7bade..2ab32f9 100644
> > --- a/hw/i386/acpi-build.c
> > +++ b/hw/i386/acpi-build.c
> > @@ -1848,9 +1848,9 @@ static Aml *build_q35_osc_method(void)
> >   
> >       /*
> >        * Always allow native PME, AER (no dependencies)
> > -     * Never allow SHPC (no SHPC controller in this system)
> > +     * Allow SHPC (PCI bridges can have SHPC controller)
> >        */
> > -    aml_append(if_ctx, aml_and(a_ctrl, aml_int(0x1D), a_ctrl));
> > +    aml_append(if_ctx, aml_and(a_ctrl, aml_int(0x1F), a_ctrl));
> >   
> >       if_ctx2 = aml_if(aml_lnot(aml_equal(aml_arg(1), aml_int(1))));
> >       /* Unknown revision */
> > --
> > 2.7.4