Hi Paolo,

On 6/1/26 10:55 AM, Paolo Abeni wrote:

On 5/26/26 11:47 AM, Bastien Curutchet (Schneider Electric) wrote:

quoted

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index a39541d29ad5..e0b3724a7558 100644
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c

@@ -1909,6 +1909,54 @@ void ksz9477_phylink_mac_link_up(struct phylink_config *config,
  	ksz9477_duplex_flowctrl(dev, port, duplex, tx_pause, rx_pause);
  }
  
+/**
+ * ksz9477_support_eee - Determine Energy Efficient Ethernet (EEE) support for a
+ *                       port
+ * @ds: Pointer to the DSA switch structure
+ * @port: Port number to check
+ *
+ * This function also documents devices where EEE was initially advertised but
+ * later withdrawn due to reliability issues, as described in official errata
+ * documents. These devices are explicitly listed to record known limitations,
+ * even if there is no technical necessity for runtime checks.
+ *
+ * Returns: true if the internal PHY on the given port supports fully
+ * operational EEE, false otherwise.
+ */
+static bool ksz9477_support_eee(struct dsa_switch *ds, int port)
+{
+	struct ksz_device *dev = ds->priv;
+
+	if (!dev->info->internal_phy[port])
+		return false;
+
+	switch (dev->chip_id) {
+	case KSZ8563_CHIP_ID:
+	case KSZ9563_CHIP_ID:
+	case KSZ9893_CHIP_ID:
+		return true;
+	default:
+		/* KSZ8567R Errata DS80000752C Module 4 */
+		/* KSZ9477S Errata DS80000754A Module 4 */
+		/* KSZ9567S Errata DS80000756A Module 4 */
+		/* KSZ9896C Errata DS80000757A Module 3 */
+		/* KSZ9897R Errata DS80000758C Module 4 */

Sashiko noted that errata:

		/* KSZ879x/KSZ877x/KSZ876x Errata DS80000687C Module 2 */

has been lost above.

Yes that was more or less intended because KSZ879x/KSZ877x/KSZ876x don't 
belong to the KSZ9477 family. I haven't found a relevant place to move 
this comment as .support_eee() is removed from ksz8.c, maybe I should 
have mentioned it in the commit log.

quoted

diff --git a/drivers/net/dsa/microchip/lan937x_main.c b/drivers/net/dsa/microchip/lan937x_main.c
index f8f220242f7a..4cbbcf7993c9 100644
--- a/drivers/net/dsa/microchip/lan937x_main.c
+++ b/drivers/net/dsa/microchip/lan937x_main.c

@@ -915,7 +915,6 @@ const struct dsa_switch_ops lan937x_switch_ops = {
  	.port_txtstamp		= ksz_port_txtstamp,
  	.port_rxtstamp		= ksz_port_rxtstamp,
  	.port_setup_tc		= ksz_setup_tc,
-	.support_eee		= ksz_support_eee,
  	.set_mac_eee		= ksz_set_mac_eee,

Sashiko noted that `set_mac_eee` usage is gated by `support_eee` presence,
you may want to remove even the set callback.

True, will do.



Best regards,
Bastien