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Date:   Fri, 6 May 2022 16:03:14 +0100 (BST)
From:   "Maciej W. Rozycki" <macro@orcam.me.uk>
To:     Geert Uytterhoeven <geert@linux-m68k.org>
cc:     David Laight <David.Laight@aculab.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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Hi Geert,
> >  Sane access would require a single CPU instruction to read or write from
> > the configuration space.  To access the conventional PCI configuration
> > space in a direct linear manner you need 256 * 21 * 8 * 256 = 10.5MiB of
> > address space.  Such amount of address space seems affordable even with
> > 32-bit systems.
> 
> Won't have fit in the legacy 1 MiB space ("640 KiB...").

 Haha, but anyway you're supposed to use BIOS calls under DOS and the like 
so it doesn't really matter.  You can't poke at the APIC in the legacy 
space either.

  Maciej