[PATCH v2 0/2] Avoid enabling LPI on non-ARM

[Rafael J. Wysocki]

On Fri, Feb 25, 2022 at 8:11 PM Mario Limonciello
<mario.limonciello at amd.com> wrote:
>
> On some AMD platforms the platform _OSC negotiation will lead to
> `osc_pc_lpi_support_confirmed` being set and because the ACPI tables are
> populated with `_LPI` entries the kernel will attempt to enable LPI.
>
> On non-ARM kernels LPI is not supported and both
> `acpi_processor_ffh_lpi_probe` and
> `acpi_processor_ffh_lpi_enter` will return error codes.
>
> When this happens there is no recourse though; the cpuidle code does
> not switch to `_CST` mode, but rather it will continue to behave as though
> LPI has been enabled and the CPU will remain in a high power state.
>
> This patch series shifts the checks around while enabling LPI to detect
> this situation and let the system continue to set up in _CST mode.
>
> Link to v1: https://lore.kernel.org/linux-acpi/20220225031255.3647599-1-mario.limonciello@amd.com/T/#m90282a6e29c334d14b2854a27d7225fc57a22aa6
>
> Mario Limonciello (2):
>   PSCI: cpuidle: Move the `has_lpi` check to the beginning of the
>     function
>   ACPI: processor idle: Check for architectural support for LPI
>
>  arch/arm64/kernel/cpuidle.c   |  6 +++---
>  drivers/acpi/processor_idle.c | 15 ++++++++++-----
>  2 files changed, 13 insertions(+), 8 deletions(-)
>
> --

Both patches in the series applied as 5.18 material, thanks!