Re: [PATCH] mailbox: ARM_MHU_V3 should depend on ARM64

From: Cristian Marussi <cristian.marussi@arm.com>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
	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
Date: Tue, 4 Jun 2024 10:46:19 +0100	[thread overview]
Message-ID: <Zl7ia0t2O2xS8PXU@pluto> (raw)
In-Reply-To: <20240604070718.ypymfv6j2smvxldr@bogus>

On Tue, Jun 04, 2024 at 08:07:18AM +0100, Sudeep Holla wrote:
> 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.
> 

I just tried this trick, it does not seem to work: an explict default-n will
anyway trigger a prompt.

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

Can this be at least

	depends on ARM || ARM64 || COMPILE_TEST

Thanks,
Cristian

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