[PATCH net-next] net: phy: fix genphy_c45_eee_is_active() for disabled EEE

["Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>]

Commit 809265fe96fe ("net: phy: c45: remove local advertisement
parameter from genphy_c45_eee_is_active") stopped reading the local
advertisement from the PHY earlier in this development cycle, which
broke "ethtool --set-eee ethX eee off".

When ethtool is used to set EEE off, genphy_c45_eee_is_active()
indicates that EEE was active if the link partner reported an
advertisement, which causes phylib to set phydev->enable_tx_lpi on
link up, despite our local advertisement in hardware being empty.
However, phydev->advertising_eee is preserved while EEE is turned off,
which leads to genphy_c45_eee_is_active() incorrectly reporting that
EEE is active.

Fix it by checking phydev->eee_cfg.eee_enabled, and if clear,
immediately indicate that EEE is not active.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/phy-c45.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/phy/phy-c45.c b/drivers/net/phy/phy-c45.c
index 0bcbdce38107..f1973ed90072 100644
--- a/drivers/net/phy/phy-c45.c
+++ b/drivers/net/phy/phy-c45.c
@@ -1476,6 +1476,9 @@ int genphy_c45_eee_is_active(struct phy_device *phydev, unsigned long *lp)
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(common);
 	int ret;
 
+	if (!phydev->eee_cfg.eee_enabled)
+		return 0;
+
 	ret = genphy_c45_read_eee_lpa(phydev, tmp_lp);
 	if (ret)
 		return ret;
-- 
2.30.2