linux-kernel - Re: [PATCH] PM / s2idle: Fix the failure of specifying "mem_sleep

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Date:   Wed, 4 Aug 2021 18:32:22 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     xiongxin <win239@....com>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Pavel Machek <pavel@....cz>,
        Linux PM <linux-pm@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        xiongxin <xiongxin@...inos.cn>,
        Sudeep Holla <sudeep.holla@....com>
Subject: Re: [PATCH] PM / s2idle: Fix the failure of specifying
 "mem_sleep_default=" parameter

On Fri, Jul 9, 2021 at 3:03 AM xiongxin <win239@....com> wrote:
>
> From: xiongxin <xiongxin@...inos.cn>
>
> On the arm64 platform, the psci driver is used by default to set the
> suspend_ops structure; but the psci_acpi_init() function is called
> before the command-line parameter "mem_sleep_default=" is specified;

You seem to mean that psci_acpi_init() runs before
mem_sleep_default_setup() and so there is a confusion regarding the
mem_sleep_default setting.

Clearly, suspend_ops cannot be set before mem_sleep_default_setup()
runs, so I'd prefer to fix the ordering instead of hacking the latter
to fix up the mess.

> the user cannot set the desired suspend mode through the
> "mem_sleep_default=" parameter;
>
> In mem_sleep_default_setup(), judge whether suspend_ops is set, if it
> has been assigned, rewrite the value of mem_sleep_current variable; in
> order to complete the user setting;
>
> Signed-off-by: xiongxin <xiongxin@...inos.cn>
>
> diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> index d8cae434f9eb..bef4b17de3f6 100644
> --- a/kernel/power/suspend.c
> +++ b/kernel/power/suspend.c
> @@ -192,6 +192,21 @@ static int __init mem_sleep_default_setup(char *str)
>                         break;
>                 }
>
> +       /*
> +        * When the suspend_ops has been set, "mem_sleep_default=*" will
> +        * be invalid, here to fix this situation.
> +        */
> +       if (suspend_ops) {
> +               if (mem_sleep_default == PM_SUSPEND_TO_IDLE)
> +                       mem_sleep_current = PM_SUSPEND_TO_IDLE;
> +               else if ((mem_sleep_default == PM_SUSPEND_STANDBY) &&
> +                               valid_state(PM_SUSPEND_STANDBY))
> +                       mem_sleep_current = PM_SUSPEND_STANDBY;
> +               else if ((mem_sleep_default >= PM_SUSPEND_MEM) &&
> +                               valid_state(PM_SUSPEND_MEM))
> +                       mem_sleep_current = PM_SUSPEND_MEM;
> +       }
> +
>         return 1;
>  }
>  __setup("mem_sleep_default=", mem_sleep_default_setup);
> --
> 2.25.1
>