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Date: Tue, 4 Jun 2024 08:07:18 +0100
From: Sudeep Holla <sudeep.holla@arm.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Cristian Marussi <cristian.marussi@arm.com>,
	Sudeep Holla <sudeep.holla@arm.com>,
	Jassi Brar <jassisinghbrar@gmail.com>,
	linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mailbox: ARM_MHU_V3 should depend on ARM64
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On Mon, Jun 03, 2024 at 07:52:56PM +0200, Geert Uytterhoeven wrote:
> Hi Sudeep,
>
> On Mon, Jun 3, 2024 at 3:39 PM Sudeep Holla <sudeep.holla@arm.com> wrote:
> > On Wed, May 29, 2024 at 01:36:42PM +0200, Geert Uytterhoeven wrote:
> > > On Wed, May 29, 2024 at 12:13 PM Cristian Marussi
> > > <cristian.marussi@arm.com> wrote:
> > > > On Wed, May 29, 2024 at 09:30:45AM +0200, Geert Uytterhoeven wrote:
> > > > > The ARM MHUv3 controller is only present on ARM64 SoCs.  Hence add a
> > > > > dependency on ARM64, to prevent asking the user about this driver when
> > > > > configuring a kernel for a different architecture than ARM64.
> > > >
> > > > the ARM64 dependency was dropped on purpose after a few iterations of
> > > > this series since, despite this being an ARM IP, it has really no technical
> > > > dependency on ARM arch, not even the usual one on ARM AMBA bus, being this a
> > > > platform driver, so it seemed an uneeded artificial restriction to impose...
> > > > ...having said that, surely my live testing were performed only on arm64 models
> > > > as of now.
> > >
> > > For that, we have COMPILE_TEST=y.
> > >
> > > > So, I am not saying that I am against this proposed fix but what is the
> > > > issue that is trying to solve, have you seen any compilation error ? or
> > > > is it just to avoid the user-prompting ?
> > >
> > > I did not see a compile error (I didn't enable it on any non-ARM
> > > platform).
> > >
> > > But it is rather futile to ask the user about (thousands of) drivers
> > > for hardware that cannot possibly be present on the system he is
> > > configuring a kernel for.
> >
> > I am fine with this fix but I have seen quite opposite argument. That is
> > not to add dependency if it is not strictly required.
>
> Can you please point me to that reference?
>

I don't have one handy, I need to dig but I have been asked to remove
in the past.

> > Also since you state that the fix is to avoid users of other archs being
> > posed with the question that they may get annoyed or can't answer, I
> > wonder if the right approach is to make this driver default "n" instead.
>
> The driver already defaults to "n" (which is the default default ;-)

Ah Cristian mentioned the same in private. I may have misunderstood
then, for some reason I thought explicit default "n" would avoid getting
the prompt.

As I said I am fine with the proposed change, just took this discussion
as a way to learn little more about Kconfig.

--
Regards,
Sudeep