Re: [PATCH v2] PCI: rcar-host: Add static assertion to check !PCI_LOCKLESS_CONFIG

[Marek Vasut]

On 9/24/25 6:00 AM, Manivannan Sadhasivam wrote:
> On Wed, Sep 24, 2025 at 05:34:55AM +0200, Marek Vasut wrote:
> > Hello Manivannan,
> >
> > On 9/24/25 5:25 AM, Manivannan Sadhasivam wrote:
> > > On Wed, Sep 24, 2025 at 01:46:18AM +0200, Marek Vasut wrote:
> > > > 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.
> > >
> > > This limitation applies to almost all host controller drivers except those used
> > > on Intel platforms like VMD and Hyper-V. So this would require adding the
> > > Kconfig dependency for all those, not just for RCAR.
> >
> > Correct.
> >
> > > We could also add the dependency to the arch Kconfig, but there is still a
> > > possibility that if the driver is used on a platform selecting
> > > PCI_LOCKLESS_CONFIG, it would be broken silently. So adding the dependency to
> > > the individual drivers that suffer from the limitation seems to be the right
> > > thing to do.
> >
> > Would you like me to send a few more patches which add !PCI_LOCKLESS_CONFIG
> > into per-driver Kconfig entries, at least for drivers where I am sure they
> > suffer from this currently hypothetical issue ...
>
> Sure.
>
> > > Also, I'm not in favor of adding static_assert with Kconfig dependency in place.
> > ... and drop the static assert ?
> >
> > Then the drivers would at least be marked accordingly.
>
> Yes. Better than what we have currently.
This is now done in

[PATCH] PCI: controller: Mark controllers which cannot do lockless 
config access with !PCI_LOCKLESS_CONFIG

I hope I got all of them.