net: stmmac: Fix lack of link transition for fixed PHYs

[ Upstream commit c51e424dc79e1428afc4d697cdb6a07f7af70cbf ]

Commit 52f95bbfcf72 ("stmmac: fix adjust link call in case of a switch
is attached") added some logic to avoid polling the fixed PHY and
therefore invoking the adjust_link callback more than once, since this
is a fixed PHY and link events won't be generated.

This works fine the first time, because we start with phydev->irq =
PHY_POLL, so we call adjust_link, then we set phydev->irq =
PHY_IGNORE_INTERRUPT and we stop polling the PHY.

Now, if we called ndo_close(), which calls both phy_stop() and does an
explicit netif_carrier_off(), we end up with a link down. Upon calling
ndo_open() again, despite starting the PHY state machine, we have
PHY_IGNORE_INTERRUPT set, and we generate no link event at all, so the
link is permanently down.

Fixes: 52f95bbfcf72 ("stmmac: fix adjust link call in case of a switch is attached")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 4c8c60af798595e198a24951bf9547aa0de522dc..fe9e7b1979b85405fd96dddb268bbeca3646f8b6 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -871,6 +871,13 @@ static int stmmac_init_phy(struct net_device *dev)
                return -ENODEV;
        }
 
+       /* stmmac_adjust_link will change this to PHY_IGNORE_INTERRUPT to avoid
+        * subsequent PHY polling, make sure we force a link transition if
+        * we have a UP/DOWN/UP transition
+        */
+       if (phydev->is_pseudo_fixed_link)
+               phydev->irq = PHY_POLL;
+
        pr_debug("stmmac_init_phy:  %s: attached to PHY (UID 0x%x)"
                 " Link = %d\n", dev->name, phydev->phy_id, phydev->link);