[PATCH] net: mii: Fix the Speed display when the network cable is not connected

[Xiangqian Zhang]

Two different models of usb card, the drivers are r8152 and asix. If no
network cable is connected, Speed = 10Mb/s. This problem is repeated in
linux 3.10, 4.19, and 5.4. Both drivers call
mii_ethtool_get_link_ksettings, but the value of cmd->base.speed in this
function can only be SPEED_1000 or SPEED_100 or SPEED_10.
When the network cable is not connected, set cmd->base.speed
=SPEED_UNKNOWN.

v2:
https://lore.kernel.org/20250111132242.3327654-1-zhangxiangqian@xxxxxxxxxx

Signed-off-by: Xiangqian Zhang <zhangxiangqian@xxxxxxxxxx>
---
 drivers/net/mii.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/mii.c b/drivers/net/mii.c
index 22680f47385d..37bc3131d31a 100644
--- a/drivers/net/mii.c
+++ b/drivers/net/mii.c
@@ -213,6 +213,9 @@ void mii_ethtool_get_link_ksettings(struct mii_if_info *mii,
 		lp_advertising = 0;
 	}
 
+	if (!(bmsr & BMSR_LSTATUS))
+		cmd->base.speed = SPEED_UNKNOWN;
+
 	mii->full_duplex = cmd->base.duplex;
 
 	ethtool_convert_legacy_u32_to_link_mode(cmd->link_modes.supported,
-- 
2.25.1