FAILED: patch "[PATCH] net: phy: dp83867: Disable EEE support as not implemented" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 84a905290cb4c3d9a71a9e3b2f2e02e031e7512f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025110203-spinal-groovy-c2f2@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 84a905290cb4c3d9a71a9e3b2f2e02e031e7512f Mon Sep 17 00:00:00 2001
From: Emanuele Ghidoli <[email protected]>
Date: Thu, 23 Oct 2025 16:48:53 +0200
Subject: [PATCH] net: phy: dp83867: Disable EEE support as not implemented

While the DP83867 PHYs report EEE capability through their feature registers, the actual hardware does not support EEE (see Links). When the connected MAC enables EEE, it causes link instability and communication failures.

The issue is reproducible with a iMX8MP and relevant stmmac ethernet port. Since the introduction of phylink-managed EEE support in the stmmac driver, EEE is now enabled by default, leading to issues on systems using the DP83867 PHY.

Call phy_disable_eee during phy initialization to prevent EEE from being enabled on DP83867 PHYs.

index deeefb962566..36a0c1b7f59c 100644
@@ -738,6 +738,12 @@ static int dp83867_config_init(struct phy_device *phydev)
 			return ret;
 	}
 
+	/* Although the DP83867 reports EEE capability through the
+	 * MDIO_PCS_EEE_ABLE and MDIO_AN_EEE_ADV registers, the feature
+	 * is not actually implemented in hardware.
+	 */
+	phy_disable_eee(phydev);
+
 	if (phy_interface_is_rgmii(phydev) ||
 	    phydev->interface == PHY_INTERFACE_MODE_SGMII) {
 		val = phy_read(phydev, MII_DP83867_PHYCTRL);

From: Emanuele Ghidoli <[email protected]>

[ Upstream commit 84a905290cb4c3d9a71a9e3b2f2e02e031e7512f ]

While the DP83867 PHYs report EEE capability through their feature registers, the actual hardware does not support EEE (see Links). When the connected MAC enables EEE, it causes link instability and communication failures.

The issue is reproducible with a iMX8MP and relevant stmmac ethernet port. Since the introduction of phylink-managed EEE support in the stmmac driver, EEE is now enabled by default, leading to issues on systems using the DP83867 PHY.

Call phy_disable_eee during phy initialization to prevent EEE from being enabled on DP83867 PHYs.

---
 drivers/net/phy/dp83867.c | 6 ++++++
 1 file changed, 6 insertions(+)

index 76ca43108d992..3865019ebb5bd 100644
@@ -674,6 +674,12 @@ static int dp83867_config_init(struct phy_device *phydev)
 			return ret;
 	}
 
+	/* Although the DP83867 reports EEE capability through the
+	 * MDIO_PCS_EEE_ABLE and MDIO_AN_EEE_ADV registers, the feature
+	 * is not actually implemented in hardware.
+	 */
+	phydev->eee_broken_modes = MDIO_EEE_100TX | MDIO_EEE_1000T;
+
 	if (phy_interface_is_rgmii(phydev) ||
 	    phydev->interface == PHY_INTERFACE_MODE_SGMII) {
 		val = phy_read(phydev, MII_DP83867_PHYCTRL);

2.51.0