PHY probe not working properly for ibm_emac (PPC4xx)

I have a system with AMCC PowerPC 405EP and PHY Intel LXT971A.  Linux
2.6.18.3 is not able to detect the PHY ID correctly.  The PHY ID
detected is 0, but should be 0x1d.

This is because phy_read() (__emac_mdio_read() resp.) from
drivers/net/ibm_emac/ibm_emac_core.c might return -ETIMEDOUT or
-EREMOTEIO on error.  This is ignored inside the

int mii_phy_probe(struct mii_phy *phy, int address)
from drivers/net/ibm_emac/ibm_emac_phy.c

as the return value is assigned to an u32 variable.

Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/ibm_emac/ibm_emac_phy.c

@@ -309,7 +309,7 @@ int mii_phy_probe(struct mii_phy *phy, int address)
 {
 	struct mii_phy_def *def;
 	int i;
-	u32 id;
+	int id;
 
 	phy->autoneg = AUTONEG_DISABLE;
 	phy->advertising = 0;
@@ -324,6 +324,8 @@ int mii_phy_probe(struct mii_phy *phy, int address)
 
 	/* Read ID and find matching entry */
 	id = (phy_read(phy, MII_PHYSID1) << 16) | phy_read(phy, MII_PHYSID2);
+	if (id < 0)
+		return -ENODEV;
 	for (i = 0; (def = mii_phy_table[i]) != NULL; i++)
 		if ((id & def->phy_id_mask) == def->phy_id)
 			break;