linux-kernel - [PATCH net v1 1/1] net: usb: asix: ax88772: drop phylink use in PM to avoid MDIO runtime PM wakeups

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Message-ID: <20250908112619.2900723-1-o.rempel@pengutronix.de>
Date: Mon,  8 Sep 2025 13:26:19 +0200
From: Oleksij Rempel <o.rempel@...gutronix.de>
To: Andrew Lunn <andrew+netdev@...n.ch>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: Oleksij Rempel <o.rempel@...gutronix.de>,
	Hubert Wiśniewski <hubert.wisniewski.25632@...il.com>,
	stable@...r.kernel.org,
	kernel@...gutronix.de,
	linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org,
	Lukas Wunner <lukas@...ner.de>,
	Russell King <linux@...linux.org.uk>,
	Xu Yang <xu.yang_2@....com>,
	linux-usb@...r.kernel.org
Subject: [PATCH net v1 1/1] net: usb: asix: ax88772: drop phylink use in PM to avoid MDIO runtime PM wakeups

Drop phylink_{suspend,resume}() from ax88772 PM callbacks.

MDIO bus accesses have their own runtime-PM handling and will try to
wake the device if it is suspended. Such wake attempts must not happen
from PM callbacks while the device PM lock is held. Since phylink
{sus|re}sume may trigger MDIO, it must not be called in PM context.

No extra phylink PM handling is required for this driver:
- .ndo_open/.ndo_stop control the phylink start/stop lifecycle.
- ethtool/phylib entry points run in process context, not PM.
- phylink MAC ops program the MAC on link changes after resume.

Fixes: e0bffe3e6894 ("net: asix: ax88772: migrate to phylink")
Reported-by: Hubert Wiśniewski <hubert.wisniewski.25632@...il.com>
Cc: stable@...r.kernel.org
Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
---
 drivers/net/usb/asix_devices.c | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 792ddda1ad49..1e8f7089f5e8 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -607,15 +607,8 @@ static const struct net_device_ops ax88772_netdev_ops = {

 static void ax88772_suspend(struct usbnet *dev)
 {
-	struct asix_common_private *priv = dev->driver_priv;
 	u16 medium;

-	if (netif_running(dev->net)) {
-		rtnl_lock();
-		phylink_suspend(priv->phylink, false);
-		rtnl_unlock();
-	}
-
 	/* Stop MAC operation */
 	medium = asix_read_medium_status(dev, 1);
 	medium &= ~AX_MEDIUM_RE;
@@ -644,12 +637,6 @@ static void ax88772_resume(struct usbnet *dev)
 	for (i = 0; i < 3; i++)
 		if (!priv->reset(dev, 1))
 			break;
-
-	if (netif_running(dev->net)) {
-		rtnl_lock();
-		phylink_resume(priv->phylink);
-		rtnl_unlock();
-	}
 }

 static int asix_resume(struct usb_interface *intf)
--
2.47.3