linux-kernel - [PATCH net-next v3 01/11] net: phy: phy_port: Correctly recompute the port's linkmodes

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Message-ID: <20260201151249.642015-2-maxime.chevallier@bootlin.com>
Date: Sun,  1 Feb 2026 16:12:38 +0100
From: Maxime Chevallier <maxime.chevallier@...tlin.com>
To: davem@...emloft.net,
	Andrew Lunn <andrew@...n.ch>,
	Jakub Kicinski <kuba@...nel.org>,
	Eric Dumazet <edumazet@...gle.com>,
	Paolo Abeni <pabeni@...hat.com>,
	Russell King <linux@...linux.org.uk>,
	Heiner Kallweit <hkallweit1@...il.com>
Cc: Maxime Chevallier <maxime.chevallier@...tlin.com>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	thomas.petazzoni@...tlin.com,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Herve Codina <herve.codina@...tlin.com>,
	Florian Fainelli <f.fainelli@...il.com>,
	Vladimir Oltean <vladimir.oltean@....com>,
	Köry Maincent <kory.maincent@...tlin.com>,
	Marek Behún <kabel@...nel.org>,
	Oleksij Rempel <o.rempel@...gutronix.de>,
	Nicolò Veronese <nicveronese@...il.com>,
	Simon Horman <horms@...nel.org>,
	mwojtas@...omium.org,
	Romain Gantois <romain.gantois@...tlin.com>,
	Daniel Golle <daniel@...rotopia.org>,
	Dimitri Fedrau <dimitri.fedrau@...bherr.com>
Subject: [PATCH net-next v3 01/11] net: phy: phy_port: Correctly recompute the port's linkmodes

a PHY-driven phy_port contains a 'supported' field containing the
linkmodes available on this port. This is populated based on :
 - The PHY's reported features
 - The DT representation of the connector
 - The PHY's attach_mdi() callback

As these different attrbution methods work in conjunction, the helper
phy_port_update_supported() recomputes the final 'supported' value based
on the populated mediums, linkmodes and pairs.

However this recompute wasn't correctly implemented, and added more
modes than necessary by or'ing the medium-specific modes to the existing
support. Let's fix this and properly filter the modes.

Fixes: 589e934d2735 ("net: phy: Introduce PHY ports representation")
Signed-off-by: Maxime Chevallier <maxime.chevallier@...tlin.com>
---
 drivers/net/phy/phy_port.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/net/phy/phy_port.c b/drivers/net/phy/phy_port.c
index ec93c8ca051e..6c1d3c487b13 100644
--- a/drivers/net/phy/phy_port.c
+++ b/drivers/net/phy/phy_port.c
@@ -117,12 +117,6 @@ void phy_port_update_supported(struct phy_port *port)
 	unsigned long mode;
 	int i;
 
-	for_each_set_bit(i, &port->mediums, __ETHTOOL_LINK_MEDIUM_LAST) {
-		linkmode_zero(supported);
-		phy_caps_medium_get_supported(supported, i, port->pairs);
-		linkmode_or(port->supported, port->supported, supported);
-	}
-
 	/* If there's no pairs specified, we grab the default number of
 	 * pairs as the max of the default pairs for each linkmode
 	 */
@@ -132,6 +126,19 @@ void phy_port_update_supported(struct phy_port *port)
 			port->pairs = max_t(int, port->pairs,
 					    ethtool_linkmode_n_pairs(mode));
 
+	if (linkmode_empty(port->supported)) {
+		for_each_set_bit(i, &port->mediums,
+				 __ETHTOOL_LINK_MEDIUM_LAST) {
+			__ETHTOOL_DECLARE_LINK_MODE_MASK(med_supported) = {0};
+
+			phy_caps_medium_get_supported(med_supported, i,
+						      port->pairs);
+			linkmode_or(supported, supported, med_supported);
+		}
+
+		linkmode_and(port->supported, port->supported, supported);
+	}
+
 	/* Serdes ports supported through SFP may not have any medium set,
 	 * as they will output PHY_INTERFACE_MODE_XXX modes. In that case, derive
 	 * the supported list based on these interfaces
-- 
2.49.0