[PATCH v3 1/2] net: phy: Fix PHY AN done state machine for interrupt driven PHYs

[Roger Quadros]

The Ethernet link on an interrupt driven PHY was not coming up if the
Ethernet cable was plugged before the Ethernet interface was brought up.

The PHY state machine seems to be stuck from RUNNING to AN state
with no new interrupts from the PHY. So it doesn't know when the
PHY Auto-negotiation has been completed and doesn't transition to RUNNING
state with ANEG done thus netif_carrier_on() is never called.

NOTE: genphy_config_aneg() will not restart PHY Auto-negotiation of
advertisement parameters didn't change.

Fix this by scheduling the PHY state machine in phy_start_aneg().
There is no way of knowing in phy.c whether auto-negotiation was
restarted or not by the PHY driver so we just wait for the next
poll/interrupt to update the PHY state machine.

Fixes: 3c293f4e08b5 ("net: phy: Trigger state machine on state change and not polling.")
Cc: stable <stable@xxxxxxxxxxxxxxx> # v4.9+
Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
v3: Fix typo in commit message

 drivers/net/phy/phy.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 1be69d8..49dedf8 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -630,6 +630,10 @@ int phy_start_aneg(struct phy_device *phydev)
 
 out_unlock:
 	mutex_unlock(&phydev->lock);
+	if (!err && phy_interrupt_is_valid(phydev))
+		queue_delayed_work(system_power_efficient_wq,
+				   &phydev->state_queue, HZ);
+
 	return err;
 }
 EXPORT_SYMBOL(phy_start_aneg);
-- 
2.7.4