Le 28/04/2016 18:09, Marek Vasut a écrit :

Since commit b74766a0a0feeef5c779709cc5d109451c0d5b17 in linux-next,
( phylib: don't return NULL from get_phy_device() ), phy_get_device()
will return ERR_PTR(-ENODEV) instead of NULL if the PHY device ID is
all ones.

This causes problem with stmmac driver and likely some other drivers
which call mdiobus_register(). I triggered this bug on SoCFPGA MCVEVK
board with linux-next 20160427 and 20160428. In case of the stmmac, if
there is no PHY node specified in the DT for the stmmac block, the stmmac
driver ( drivers/net/ethernet/stmicro/stmmac/stmmac_mdio.c function
stmmac_mdio_register() ) will call mdiobus_register() , which will
register the MDIO bus and probe for the PHY.

The mdiobus_register() resp. __mdiobus_register() iterates over all of
the addresses on the MDIO bus and calls mdiobus_scan() for each of them,
which invokes get_phy_device(). Before the aforementioned patch, the
mdiobus_scan() would return NULL if no PHY was found on a given address
and mdiobus_register() would continue and try the next PHY address. Now,
mdiobus_scan() returns ERR_PTR(-ENODEV), which is caught by the
'if (IS_ERR(phydev))' condition and the loop exits immediatelly if the
PHY address does not contain PHY.

Repair this by explicitly checking for the ERR_PTR(-ENODEV) and if this
error comes around, continue with the next PHY address.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <redacted>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Sergei Shtylyov <redacted>

Acked-by: Florian Fainelli <f.fainelli@gmail.com>

I had an exact same patch posted yesterday but not formally like you
did, thanks!

-- 
Florian