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Date:   Wed, 4 May 2022 16:08:40 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Niklas Schnelle <schnelle@linux.ibm.com>
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Subject: Re: [RFC v2 01/39] Kconfig: introduce HAS_IOPORT option and select
 it as necessary
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In-Reply-To: <20220429135108.2781579-2-schnelle@linux.ibm.com>
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On Fri, Apr 29, 2022 at 03:49:59PM +0200, Niklas Schnelle wrote:
> We introduce a new HAS_IOPORT Kconfig option to indicate support for
> I/O Port access. In a future patch HAS_IOPORT=n will disable compilation
> of the I/O accessor functions inb()/outb() and friends on architectures
> which can not meaningfully support legacy I/O spaces such as s390 or
> where such support is optional. 

So you plan to drop inb()/outb() on architectures where I/O port space
is optional?  So even platforms that have I/O port space may not be
able to use it?

This feels like a lot of work where the main benefit is to keep
Kconfig from offering drivers that aren't of interest on s390.

Granted, there may be issues where inb()/outb() does the wrong thing
such as dereferencing null pointers when I/O port space isn't
implemented.  I think that's a defect in inb()/outb() and could be
fixed there.

Bjorn