[PATCH net 2/6] net: stmmac: dwmac1000: Account for the primary MAC address for UC filtering

From
Maxime Chevallier <maxime.chevallier@bootlin.com>
Date
2026-08-26 14:05:50
Also in
linux-arm-kernel, lkml
Reply to
Maxime Chevallier, 2026-08-26
The same filter slots are used to store the main MAC address as well as
the address for the unicast filter. Let's account for that when deciding
whether or not to use promisc when programming the UC list in hardware.

Fixes: 47dd7a540b8a ("net: add support for STMicroelectronics Ethernet controllers.")
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
index caac85fc08f1..d4ace3924891 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c
@@ -194,7 +194,7 @@ static void dwmac1000_set_filter(struct mac_device_info *hw,
 	dwmac1000_set_mchash(ioaddr, mc_filter, mcbitslog2);
 
 	/* Handle multiple unicast addresses (perfect filtering) */
-	if (netdev_uc_count(dev) > perfect_addr_number)
+	if (netdev_uc_count(dev) + 1 > perfect_addr_number)
 		/* Switch to promiscuous mode if more than unicast
 		 * addresses are requested than supported by hardware.
 		 */
-- 
2.55.0
Thread (19 messages) 19 messages, 4 authors, last reply 2026-08-27
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