On Tue, 9 Sep 2008, Zhao Yakui wrote:
> > > --- linux.orig/drivers/acpi/bus.c 2008-09-08 14:28:32.000000000 +0800
> > > +++ linux/drivers/acpi/bus.c 2008-09-08 14:29:03.000000000 +0800
> > > @@ -496,6 +496,19 @@ static int acpi_bus_check_scope(struct a
> > > return 0;
> > > }
> > >
> > > +static BLOCKING_NOTIFIER_HEAD(acpi_bus_notify_list);
> > > +int register_acpi_bus_notifier(struct notifier_block *nb)
> > > +{
> > > + return blocking_notifier_chain_register(&acpi_bus_notify_list, nb);
> > > +}
> > > +EXPORT_SYMBOL_GPL(register_acpi_bus_notifier);
> > > +
> > > +void unregister_acpi_bus_notifier(struct notifier_block *nb)
> > > +{
> > > + blocking_notifier_chain_unregister(&acpi_bus_notify_list, nb);
> > > +}
> > > +EXPORT_SYMBOL_GPL(unregister_acpi_bus_notifier);
> > > +
> > > /**
> > > * acpi_bus_notify
> > > * ---------------
> > > @@ -506,6 +519,8 @@ static void acpi_bus_notify(acpi_handle
> > > int result = 0;
> > > struct acpi_device *device = NULL;
> > >
> > > + blocking_notifier_call_chain(&acpi_bus_notify_list,
> > > + type, (void *)handle);
> >
> > Hm, perhaps I'm too tired and I'm missing something obvious, but can you
> > tell me please why that has to be a notifier chain? It looks like you add only
> > one notifier to it, so seemingly it could be replaced by a direct call to a
> > function like acpi_gpe_pme_handler() (with modified list of arguments).
> When the notifier chain is used, it can work regardless of whether the
> CONFIG_ACPI_GPE_WAKEUP is set.
> If the CONFIG_ACPI_GPE_WAKEUP is set, what you said is also OK.
If CONFIG_ACPI_GPE_WAKEUP is not set then you should define
acpi_gpe_pme_handler() as a do-nothing function. Then you could call
it always, regardless of the kconfig setting, with no need for a
notifier chain.
Alan Stern
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