linux-kernel - Re: [PATCH] phy: core: Reinstate pm_runtime_enabled() check in phy_pm_runtime

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Message-ID: <b90f706e-165d-43c3-8dcf-ba8a495fd2f8@intel.com>
Date: Tue, 30 Dec 2025 18:10:28 +0100
From: "Wysocki, Rafael J" <rafael.j.wysocki@...el.com>
To: Geert Uytterhoeven <geert+renesas@...der.be>, Vinod Koul
	<vkoul@...nel.org>, Neil Armstrong <neil.armstrong@...aro.org>
CC: <linux-phy@...ts.infradead.org>, <linux-renesas-soc@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] phy: core: Reinstate pm_runtime_enabled() check in
 phy_pm_runtime_put()


On 12/30/2025 4:04 PM, Geert Uytterhoeven wrote:
> On Koelsch (R-Car M2-W), during boot and s2ram:
>
>      phy phy-e6590100.usb-phy-controller.0: Runtime PM usage count underflow!
>
> While phy_pm_runtime_get{,_sync}() and phy_pm_runtime_put_sync() still
> contain pm_runtime_enabled() checks, the same check in
> phy_pm_runtime_put() was deemed redundant and removed, causing count
> underflows with PHY drivers like drivers/phy/renesas/phy-rcar-gen2.c
> that do not use Runtime PM yet,
>
> Fix this by reinstating the check.
>
> Fixes: caad07ae07e3fb17 ("phy: core: Discard pm_runtime_put() return values")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>


> ---
>   drivers/phy/phy-core.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index 160ecb757d1d62a0..e2a2a99d069789c7 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -195,6 +195,9 @@ void phy_pm_runtime_put(struct phy *phy)
>   	if (!phy)
>   		return;
>   
> +	if (!pm_runtime_enabled(&phy->dev))
> +		return;
> +
>   	pm_runtime_put(&phy->dev);
>   }
>   EXPORT_SYMBOL_GPL(phy_pm_runtime_put);