1 files changed, 34 insertions, 13 deletions

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 8fb1faca883..25acbbde4a6 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -227,8 +227,17 @@ struct phy_device * get_phy_device(struct mii_bus *bus, int addr)
         if (r)
                 return ERR_PTR(r);
 
-        /* If the phy_id is all Fs or all 0s, there is no device there */
-        if ((0xffff == phy_id) || (0x00 == phy_id))
+        /* If the phy_id is mostly Fs, there is no device there */
+        if ((phy_id & 0x1fffffff) == 0x1fffffff)
+                return NULL;
+
+        /*
+         * Broken hardware is sometimes missing the pull down resistor on the
+         * MDIO line, which results in reads to non-existent devices returning
+         * 0 rather than 0xffff. Catch this here and treat 0 as a non-existent
+         * device as well.
+         */
+        if (phy_id == 0)
                 return NULL;
 
         dev = phy_device_create(bus, addr, phy_id);
@@ -564,20 +573,32 @@ EXPORT_SYMBOL(genphy_restart_aneg);
  */
 int genphy_config_aneg(struct phy_device *phydev)
 {
-        int result = 0;
+        int result;
 
-        if (AUTONEG_ENABLE == phydev->autoneg) {
-                int result = genphy_config_advert(phydev);
+        if (AUTONEG_ENABLE != phydev->autoneg)
+                return genphy_setup_forced(phydev);
 
-                if (result < 0) /* error */
-                        return result;
+        result = genphy_config_advert(phydev);
+
+        if (result < 0) /* error */
+                return result;
+
+        if (result == 0) {
+                /* Advertisment hasn't changed, but maybe aneg was never on to
+                 * begin with?  Or maybe phy was isolated? */
+                int ctl = phy_read(phydev, MII_BMCR);
+
+                if (ctl < 0)
+                        return ctl;
+
+                if (!(ctl & BMCR_ANENABLE) || (ctl & BMCR_ISOLATE))
+                        result = 1; /* do restart aneg */
+        }
 
-                /* Only restart aneg if we are advertising something different
-                 * than we were before.  */
-                if (result > 0)
-                        result = genphy_restart_aneg(phydev);
-        } else
-                result = genphy_setup_forced(phydev);
+        /* Only restart aneg if we are advertising something different
+         * than we were before.  */
+        if (result > 0)
+                result = genphy_restart_aneg(phydev);
 
         return result;
 }