Re: [PATCH] PCI: rcar-host: Add static assertion to check !PCI_LOCKLESS_CONFIG

[Marek Vasut]

On 9/22/25 5:48 PM, Marek Vasut wrote:

Hello Geert,

> > > +/*
> > > + * This driver can not function correctly without PCIe subsystem level
> > > + * config space access serialization. In case PCI_LOCKLESS_CONFIG is
> > > + * ever enabled on ARM, complain loudly so the driver can be updated
> > > + * accordingly.
> > > + */
> > > +static_assert(!IS_ENABLED(CONFIG_PCI_LOCKLESS_CONFIG));
> > > +
> > >   struct rcar_msi {
> > >          DECLARE_BITMAP(used, INT_PCI_MSI_NR);
> > >          struct irq_domain *domain;
> >
> > This causes a build failure when compile-testing, e.g. x86 allmodconfig.
> > Using "depends on !PCI_LOCKLESS_CONFIG" instead would avoid that,
> > but indeed has the disadvantage that it wouldn't complain loudly when
> > PCI_LOCKLESS_CONFIG would ever be enabled on ARM64...
> All right, let's also wait for input from PCI maintainers. It seems both 
> alternatives -- static_assert() and !PCI_LOCKLESS_CONFIG have their own 
> disadvantages, maybe there is a third option.

Maybe we can try with both.

--
Best regards,
Marek Vasut