Re: [PATCH 2/2] PCI: Drop controller CONFIG_OF dependencies

From: Bjorn Helgaas <helgaas@kernel.org>
To: "Pali Rohár" <pali@kernel.org>
Cc: "Geert Uytterhoeven" <geert@linux-m68k.org>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	"Bjorn Helgaas" <bhelgaas@google.com>
Subject: Re: [PATCH 2/2] PCI: Drop controller CONFIG_OF dependencies
Date: Tue, 15 Nov 2022 14:53:43 -0600	[thread overview]
Message-ID: <20221115205343.GA1038784@bhelgaas> (raw)
In-Reply-To: <20221115193155.mqdh6pzhiba4v4pa@pali>

On Tue, Nov 15, 2022 at 08:31:55PM +0100, Pali Rohár wrote:
> On Tuesday 15 November 2022 12:07:34 Bjorn Helgaas wrote:
> > On Tue, Nov 15, 2022 at 04:56:10PM +0100, Geert Uytterhoeven wrote:
> > > On Tue, Oct 25, 2022 at 9:16 PM Bjorn Helgaas <helgaas@kernel.org> wrote:
> > > > From: Bjorn Helgaas <bhelgaas@google.com>
> > > >
> > > > Many drivers depend on OF interfaces, so they won't be functional if
> > > > CONFIG_OF is not set.  But OF provides stub functions in that case, so drop
> > > > the OF dependencies so we can at least compile-test the drivers.
> > 
> > > > --- a/drivers/pci/controller/Kconfig
> > > > +++ b/drivers/pci/controller/Kconfig
> > > > @@ -8,7 +8,6 @@ config PCI_MVEBU
> > > >         depends on ARCH_MVEBU || ARCH_DOVE || COMPILE_TEST
> > > >         depends on MVEBU_MBUS
> > > >         depends on ARM
> > > > -       depends on OF
> > > 
> > > This is exactly why we have the COMPILE_TEST symbol.
> > > There is no point in bothering all users who configure kernels with
> > > questions about drivers that won't function anyway due to missing
> > > dependencies, unless the user explicitly wants to do compile-testing.
> > > 
> > > So all of these should become:
> > > 
> > >     depends on OF || COMPILE_TEST
> > 
> > Oh, yes, thanks for pointing this out, I totally blew it here.  I
> > dropped this while we figure it out.
> 
> I agree too, it really makes sense to not provide pci-mvebu driver to
> end users without OF - it would not work.
> 
> Anyway, it is needed to declare "depends on ARM" for pci-mvebu?
> Both supported architectures (mvebu and dove) are ARM.

If you're asking whether "depends on ARM" can be removed for
PCI_MVEBU, I don't know the answer.  I do see that CONFIG_ARCH_MVEBU
is mentioned in arch/arm64, which doesn't seem to set CONFIG_ARM.

In any event, I would consider a change like that to be a separate
patch.  Here I just want to focus on CONFIG_OF.

Bjorn