Re: [PATCH v2] of: OF_IRQ: select IRQ_DOMAIN instead of depending on it

[Rob Herring]

On Wed, Feb 14, 2024 at 06:22:53PM +0100, Arnd Bergmann wrote:
> On Wed, Feb 14, 2024, at 17:35, Marc Zyngier wrote:
> > On Wed, 14 Feb 2024 16:06:06 +0000,
> > "Arnd Bergmann" <arnd@xxxxxxxx> wrote:
> >> 
> >> On Wed, Feb 14, 2024, at 10:52, Marc Zyngier wrote:
> >> > On Tue, 13 Feb 2024 22:56:19 +0000, Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
> >> >>
> >> >> diff -- a/drivers/of/Kconfig b/drivers/of/Kconfig
> >> >> --- a/drivers/of/Kconfig
> >> >> +++ b/drivers/of/Kconfig
> >> >> @@ -80,7 +80,8 @@ config OF_ADDRESS
> >> >>  
> >> >>  config OF_IRQ
> >> >>  	def_bool y
> >> >> -	depends on !SPARC && IRQ_DOMAIN
> >> >> +	depends on !SPARC
> >> >> +	select IRQ_DOMAIN
> >> > 
> >> >
> >> > This seems to be moving is the right direction.
> >> 
> >> Can we move the 'select IRQ_DOMAIN' under CONFIG_IRQCHIP
> >> then and remove the individual selects from the irqchip
> >> drivers? It looks like CONFIG_OF (other than sparc) now
> >> unconditionally enables OF_IRQ and IRQCHIP anyway.
> >
> > As long as it also works ACPI, it should be OK.
> 
> Out of the four architectures that have ACPI support (x86,
> arm64, loongarch, rv64), only x86 doesn't always select
> IRQ_DOMAIN already, and x86 selects it for almost all
> configs:
> 
> config X86_UP_APIC
>         bool "Local APIC support on uniprocessors" if !PCI_MSI
>         default PCI_MSI
>         depends on X86_32 && !SMP && !X86_32_NON_STANDARD
> 
> config X86_LOCAL_APIC
>         def_bool y
>         depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC || PCI_MSI
>         select IRQ_DOMAIN_HIERARCHY
> 
> so it's only disabled here with
> 
> CONFIG_64BIT=n
> CONFIG_SMP=n
> CONFIG_X86_32_NON_STANDARD=n
> CONFIG_ACPI=y
> CONFIG_PCI=y (implied by ACPI)
> CONFIG_PCI_MSI=n
> 
> As far as I can tell, this specific configuration is
> currently able to save a little bit of kernel size
> by avoiding IRQ_DOMAIN, but we are probably better off
> enabling it here as well for consistency

+1

Also, looks like we have a couple of 'select OF_IRQ' that could be 
dropped.

Rob