net: phy: Fix "link partner" information disappear issue

Some drivers just call phy_ethtool_ksettings_set() to set the
links, for those phy drivers that use genphy_read_status(), if
autoneg is on, and the link is up, than execute "ethtool -s
ethx autoneg on" will cause "link partner" information disappear.

The call trace is phy_ethtool_ksettings_set()->phy_start_aneg()
->linkmode_zero(phydev->lp_advertising)->genphy_read_status(),
the link didn't change, so genphy_read_status() just return, and
phydev->lp_advertising is zero now.

This patch moves the clear operation of lp_advertising from
phy_start_aneg() to genphy_read_lpa()/genphy_c45_read_lpa(), and
if autoneg on and autoneg not complete, just clear what the
generic functions care about.

Fixes: 88d6272acaaa ("net: phy: avoid unneeded MDIO reads in genphy_read_status")
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Reviewed-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/net/phy/phy-c45.c b/drivers/net/phy/phy-c45.c
index 7935593debb1..a1caeee12236 100644
--- a/drivers/net/phy/phy-c45.c
+++ b/drivers/net/phy/phy-c45.c
@@ -323,6 +323,8 @@ int genphy_c45_read_pma(struct phy_device *phydev)
 {
 	int val;
 
+	linkmode_zero(phydev->lp_advertising);
+
 	val = phy_read_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_CTRL1);
 	if (val < 0)
 		return val;