Re: [PATCH] arm64: cacheinfo: Simplify init_cache_level()

[Thorsten Blum <blum@kernel.org>]

Hi Ben,

On Wed, Nov 04, 2026 at 10:32:58AM +0000, Ben Horgan wrote:
> Hi Thorsten,
> 
> On 04/11/2026 08:36, Thorsten Blum wrote:
> > acpi_get_cache_info() already sets fw_level to 0 on failure, so drop the
> > redundant check and the manual assignment.
> 
> This doesn't seem to be the case when CONFIG_ACPI_PPTT is not defined. Can the dummy implementation
> in include/linux/cacheinfo.h be called from init_cache_level()? For the implementation in

On arm64, ACPI_PPTT is selected when ACPI is enabled. When ACPI is
disabled, acpi_disabled = 1 and init_cache_level() won't call the stub.

> drivers/acpi/pptt.c levels is documented as "Number of levels if success." and so would be good to
> mention what happens in the error case if it needs to be relied on.

Below the parameter descriptions, it already says:

  "Errors caused by lack of a PPTT table, or otherwise, return 0
   indicating we didn't find any cache levels."

Thanks,
Thorsten