[PATCH] net/fec_mpc52xx: Fix kernel panic on FEC error

Grant Likely grant.likely at secretlab.ca
Thu Oct 15 04:40:00 EST 2009

From: John Bonesio <bonesio at secretlab.ca>

The MDIO bus cannot be accessed at interrupt context, but on an FEC
error, the fec_mpc52xx driver reset function also tries to reset the
PHY.  Since the error is detected at IRQ context, and the PHY functions
try to sleep, the kernel ends up panicking.

Resetting the PHY on an FEC error isn't even necessary.  This patch
solves the problem by removing the PHY reset entirely.

Signed-off-by: John Bonesio <bonesio at secretlab.ca>
Signed-off-by: Grant Likely <grant.likely at secretlab.ca>

Hi David,

This patch is a bug fix that definitely needs to go in for 2.6.32.
I'll also be asking Greg to pick it up for the stable tree once it
is in mainline.


 drivers/net/fec_mpc52xx.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/drivers/net/fec_mpc52xx.c b/drivers/net/fec_mpc52xx.c
index c40113f..66dace6 100644
--- a/drivers/net/fec_mpc52xx.c
+++ b/drivers/net/fec_mpc52xx.c
@@ -759,12 +759,6 @@ static void mpc52xx_fec_reset(struct net_device *dev)
-	if (priv->phydev) {
-		phy_stop(priv->phydev);
-		phy_write(priv->phydev, MII_BMCR, BMCR_RESET);
-		phy_start(priv->phydev);
-	}

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