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@glider.be>
---
 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);
-- 
2.43.0

On Tue, 30 Dec 2025 16:04:05 +0100, 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,
> 
> [...]

Applied, thanks!

[1/1] phy: core: Reinstate pm_runtime_enabled() check in phy_pm_runtime_put()
      commit: 0287c960b15f27498d85cadf584bb59301ea2382

Best regards,
-- 
~Vinod

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@glider.be>

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.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);