linux-kernel - Re: [PATCH] ACPI: acpi_pad: Still evaluate _OST when

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Date: Thu, 13 Jun 2024 20:49:14 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Armin Wolf <W_Armin@....de>
Cc: rafael@...nel.org, lenb@...nel.org, linux-acpi@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ACPI: acpi_pad: Still evaluate _OST when _PUR evaluation fails

On Sun, Jun 9, 2024 at 11:09 PM Armin Wolf <W_Armin@....de> wrote:
>
> The ACPI specification says that if no action was performed when
> processing the _PUR object, _OST should still be evaluated, albeit
> with a different status code.
>
> Evaluate _OST even when evaluating _PUR fails, to signal the firmware
> that no action was performed.
>
> Compile-tested only.
>
> Signed-off-by: Armin Wolf <W_Armin@....de>
> ---
>  drivers/acpi/acpi_pad.c | 19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
> index bd1ad07f0290..350d3a892889 100644
> --- a/drivers/acpi/acpi_pad.c
> +++ b/drivers/acpi/acpi_pad.c
> @@ -25,6 +25,10 @@
>  #define ACPI_PROCESSOR_AGGREGATOR_CLASS        "acpi_pad"
>  #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
>  #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
> +
> +#define ACPI_PROCESSOR_AGGREGATOR_STATUS_SUCCESS       0
> +#define ACPI_PROCESSOR_AGGREGATOR_STATUS_NO_ACTION     1
> +
>  static DEFINE_MUTEX(isolated_cpus_lock);
>  static DEFINE_MUTEX(round_robin_lock);
>
> @@ -382,16 +386,23 @@ static void acpi_pad_handle_notify(acpi_handle handle)
>                 .length = 4,
>                 .pointer = (void *)&idle_cpus,
>         };
> +       u32 status;
>
>         mutex_lock(&isolated_cpus_lock);
>         num_cpus = acpi_pad_pur(handle);
>         if (num_cpus < 0) {
> -               mutex_unlock(&isolated_cpus_lock);
> -               return;
> +               /* The ACPI specification says that if no action was performed when
> +                * processing the _PUR object, _OST should still be evaluated, albeit
> +                * with a different status code.
> +                */
> +               status = ACPI_PROCESSOR_AGGREGATOR_STATUS_NO_ACTION;
> +       } else {
> +               status = ACPI_PROCESSOR_AGGREGATOR_STATUS_SUCCESS;
> +               acpi_pad_idle_cpus(num_cpus);
>         }
> -       acpi_pad_idle_cpus(num_cpus);
> +
>         idle_cpus = acpi_pad_idle_cpus_num();
> -       acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY, 0, &param);
> +       acpi_evaluate_ost(handle, ACPI_PROCESSOR_AGGREGATOR_NOTIFY, status, &param);
>         mutex_unlock(&isolated_cpus_lock);
>  }
>
> --

Applied as 6.11 material, thanks!