linux-kernel - Re: [PATCH v1] PM: sleep: core: Clear power.must

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Message-ID: <CAPDyKFqk343jLYL=x=+7VcUAG_n9xVs8ZhB8x1mytYmm8C8h3g@mail.gmail.com>
Date: Thu, 4 Sep 2025 11:26:41 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: Linux PM <linux-pm@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] PM: sleep: core: Clear power.must_resume in noirq
 suspend error path

On Tue, 2 Sept 2025 at 15:55, Rafael J. Wysocki <rafael@...nel.org> wrote:
>
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> If system suspend is aborted in the "noirq" phase (for instance, due to
> an error returned by one of the device callbacks), power.is_noirq_suspended
> will not be set for some devices and device_resume_noirq() will return
> early for them.  Consequently, noirq resume callbacks will not run for
> them at all because the noirq suspend callbacks have not run for them
> yet.
>
> If any of them has power.must_resume set and late suspend has been
> skipped for it (due to power.smart_suspend), early resume should be
> skipped for it either, or its state may become inconsistent (for
> instance, if the early resume assumes that it will always follow
> noirq resume).
>
> Make that happen by clearing power.must_resume in device_resume_noirq()
> for devices with power.is_noirq_suspended clear that have been left in
> suspend by device_suspend_late(), which will subsequently cause
> device_resume_early() to leave the device in suspend and avoid
> changing its state.
>
> Fixes: 0d4b54c6fee8 ("PM / core: Add LEAVE_SUSPENDED driver flag")
> Link: https://lore.kernel.org/linux-pm/5d692b81-6f58-4e86-9cb0-ede69a09d799@rowland.harvard.edu/
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>

Kind regards
Uffe

> ---
>  drivers/base/power/main.c |   14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
>
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -720,8 +720,20 @@
>         if (dev->power.syscore || dev->power.direct_complete)
>                 goto Out;
>
> -       if (!dev->power.is_noirq_suspended)
> +       if (!dev->power.is_noirq_suspended) {
> +               /*
> +                * This means that system suspend has been aborted in the noirq
> +                * phase before invoking the noirq suspend callback for the
> +                * device, so if device_suspend_late() has left it in suspend,
> +                * device_resume_early() should leave it in suspend either in
> +                * case the early resume of it depends on the noirq resume that
> +                * has not run.
> +                */
> +               if (dev_pm_skip_suspend(dev))
> +                       dev->power.must_resume = false;
> +
>                 goto Out;
> +       }
>
>         if (!dpm_wait_for_superior(dev, async))
>                 goto Out;
>
>
>