Re: [PATCH 1/2] net: hisilicon: hns_mdio: remove incorrect ACPI_PTR annotation

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

On Thu, Feb 27, 2025, at 12:53, Jijie Shao wrote:
>
> if CONFIG_ACPI is disabled, ACPI_PTR() will return NULL, so
> hns_mdio_acpi_match is unused variable.
>
>
> So use #ifdef is possible and has no side effects, and many drivers do so.

Those should be cleaned up eventually, but that is separate from
the build warning.

> Of course, it also seems possible to remove ACPI_PTR(),
> But I'm not sure if it's okay to set a value to acpi_match_table if 
> CONFIG_ACPI is disabled.

Setting .acpi_match_table and .of_match_table unconditionally
is the normal case. Historically we had some drivers that
used of_match_ptr() to assign the .of_match_table in order
to allow drivers to #ifdef out the CONFIG_OF portion of the
driver for platforms that did not already use devicetree
based probing.

There are basically no platforms left that have not been
converted to devicetree yet, so there is no point in
micro-optimizing the kernel size for that case, but the
(mis)use of of_match_ptr() has been copied into drivers
after that, and most of the ACPI_PTR() users unfortunately
copied from that when drivers started supporting both.

     Arnd