[PATCH v1 15/23] phy: core: Discard pm_runtime_put() return values

[Geert Uytterhoeven]

Hi Rafael,

On Mon, 22 Dec 2025 at 21:40, Rafael J. Wysocki <rafael at kernel.org> wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
>
> The PHY core defines phy_pm_runtime_put() to return an int, but that
> return value is never used.  It also passes the return value of
> pm_runtime_put() to the caller which is not very useful.
>
> Returning an error code from pm_runtime_put() merely means that it has
> not queued up a work item to check whether or not the device can be
> suspended and there are many perfectly valid situations in which that
> can happen, like after writing "on" to the devices' runtime PM "control"
> attribute in sysfs for one example.
>
> Modify phy_pm_runtime_put() to discard the pm_runtime_put() return
> value and change its return type to void.  Also drop the redundant
> pm_runtime_enabled() call from there.
>
> No intentional functional impact.
>
> This will facilitate a planned change of the pm_runtime_put() return
> type to void in the future.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>

Thanks for your patch, which is now commit caad07ae07e3fb17 ("phy:
core: Discard pm_runtime_put() return values") in phy/next.

This is causing several messages like

    phy phy-e6590100.usb-phy-controller.2: Runtime PM usage count underflow!

during boot, and s2ram on Koelsch (R-Car M2-W).

Reverting this commit fixes the issue.

> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -190,15 +190,12 @@ int phy_pm_runtime_get_sync(struct phy *
>  }
>  EXPORT_SYMBOL_GPL(phy_pm_runtime_get_sync);
>
> -int phy_pm_runtime_put(struct phy *phy)
> +void phy_pm_runtime_put(struct phy *phy)
>  {
>         if (!phy)
> -               return 0;
> +               return;
>
> -       if (!pm_runtime_enabled(&phy->dev))
> -               return -ENOTSUPP;

Adding some instrumentation shows that this branch was taken before,
thus skipping the call to pm_runtime_put().

Can I just put the check back, or is there an underlying problem that
should be fixed instead?
Thanks!

> -
> -       return pm_runtime_put(&phy->dev);
> +       pm_runtime_put(&phy->dev);
>  }
>  EXPORT_SYMBOL_GPL(phy_pm_runtime_put);
>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds