linux-kernel - Re: [PATCH v1 3/9] ACPI: processor: idle: Return failure when get lpi_state->arch

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Message-ID: <CAJZ5v0hNj817g=rr8+YTGaeBkkfNuuU7FGuZyyb1j61BMOKTGA@mail.gmail.com>
Date: Tue, 21 Oct 2025 21:36:36 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Huisong Li <lihuisong@...wei.com>
Cc: rafael@...nel.org, lenb@...nel.org, linux-acpi@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Sudeep.Holla@....com, linuxarm@...wei.com, 
	jonathan.cameron@...wei.com, zhanjie9@...ilicon.com, zhenglifeng1@...wei.com, 
	yubowen8@...wei.com
Subject: Re: [PATCH v1 3/9] ACPI: processor: idle: Return failure when get
 lpi_state->arch_flags failed

On Mon, Sep 29, 2025 at 11:38 AM Huisong Li <lihuisong@...wei.com> wrote:
>
> The architecture specific context loss flags is important for ARM.
> And this flag is used to control the execution of different code
> flows in acpi_processor_ffh_lpi_enter().
>
> So it is better to return failure when get lpi_state->arch_flags
> failed.

A failure means no idle states at all.

Wouldn't it be better to skip the state with invalid arch flags?

> Fixes: a36a7fecfe60 ("ACPI / processor_idle: Add support for Low Power Idle(LPI) states")
> Signed-off-by: Huisong Li <lihuisong@...wei.com>
> ---
>  drivers/acpi/processor_idle.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index 681587f2614b..f36f9514b6c7 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -984,8 +984,11 @@ static int acpi_processor_evaluate_lpi(acpi_handle handle,
>                 if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
>                         lpi_state->flags = 0;
>
> -               if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
> -                       lpi_state->arch_flags = 0;
> +               if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags)) {
> +                       pr_err("Get architecture specific context loss flags failed.\n");
> +                       ret = -EINVAL;
> +                       goto end;
> +               }
>
>                 if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
>                         lpi_state->res_cnt_freq = 1;
> --
> 2.33.0
>