[PATCH 3.19.y-ckt 011/251] net: phy: fix phy link up when limiting speed via device tree

[Kamal Mostafa]

3.19.8-ckt4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mugunthan V N <mugunthanvnm at ti.com>

[ Upstream commit eb686231fce3770299760f24fdcf5ad041f44153 ]

When limiting phy link speed using "max-speed" to 100mbps or less on a
giga bit phy, phy never completes auto negotiation and phy state
machine is held in PHY_AN. Fixing this issue by comparing the giga
bit advertise though phydev->supported doesn't have it but phy has
BMSR_ESTATEN set. So that auto negotiation is restarted as old and
new advertise are different and link comes up fine.

Signed-off-by: Mugunthan V N <mugunthanvnm at ti.com>
Reviewed-by: Florian Fainelli <f.fainelli at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/phy/phy_device.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 3fc91e8..70a0d88 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -782,10 +782,11 @@ static int genphy_config_advert(struct phy_device *phydev)
 	if (phydev->supported & (SUPPORTED_1000baseT_Half |
 				 SUPPORTED_1000baseT_Full)) {
 		adv |= ethtool_adv_to_mii_ctrl1000_t(advertise);
-		if (adv != oldadv)
-			changed = 1;
 	}
 
+	if (adv != oldadv)
+		changed = 1;
+
 	err = phy_write(phydev, MII_CTRL1000, adv);
 	if (err < 0)
 		return err;
-- 
1.9.1