Re: [PATCH] various fixes for CPU/PCI hotplug

[Marcelo Tosatti <mtosatti@redhat.com>]

On Tue, Feb 03, 2009 at 04:58:31PM -0200, Glauber Costa wrote:
> >
> >  void qemu_system_device_hot_add(int pcibus, int slot, int state)
> >  {
> > -    qemu_set_irq(pm_state->irq, 1);
> >     pci0_status.up = 0;
> >     pci0_status.down = 0;
> >     if (state)
> >         enable_device(&pci0_status, &gpe, slot);
> >     else
> >         disable_device(&pci0_status, &gpe, slot);
> > -    qemu_set_irq(pm_state->irq, 0);
> > +
> > +    if (gpe.en & 2) {
> > +        qemu_set_irq(pm_state->irq, 1);
> > +        qemu_set_irq(pm_state->irq, 0);
> > +    }
> >  }
> 
> Are you sure this works? The trigger is now happening after all the
> events take place. It might well work depending on how qemu exposes
> this, but I have some spare memories of having problems with this in
> the past.

The ACPI code will read the up/down status after the IRQ is triggered
(and nothing will change it, in the meantime). What is your concern?

The OS is responsible for programming the GPE enable bit.