Re: [PATCH] um: Turn HAS_IOPORT_MAP off

["Arnd Bergmann" <arnd@arndb.de>]

On Wed, Jul 2, 2025, at 15:02, Tiwei Bie wrote:
> On 2025/7/2 19:09, Arnd Bergmann wrote:
>> On Tue, Jul 1, 2025, at 14:22, Tiwei Bie wrote:
>> xtensa selects NO_IOPORT_MAP, which means that HAS_IOPORT_MAP
>> gets disabled here:
>> 
>> arch/xtensa/Kconfig:config NO_IOPORT_MAP
>> arch/xtensa/Kconfig-    def_bool n
>
> The value of NO_IOPORT_MAP on xtensa is inverted compared to that
> on most other platforms that explicitly defines NO_IOPORT_MAP.

Ah of course, sorry for misunderstanding. Apparently this only
existed because it was selected by a long gone platform:

-config XTENSA_PLATFORM_S6105
-       bool "S6105"
-       select HAVE_IDE
-       select SERIAL_CONSOLE
-       select NO_IOPORT_MAP

Before commits

d38efc1f150f ("xtensa: adopt generic io routines")
d046f77ec4a4 ("xtensa: set NO_IOPORT to 'n' by default")

it was always-on, and I think the idea at the time was to
make it behave more like the generic PCI code, while it
was originally copied from sparc, which does things quite
differently.

It is rather clear that the I/O port implementation on
xtensa never actually worked, and some of the comments
on its PCI code suggest that it was never really used
either.

    Arnd