[patch 26/48] sungem: Soft lockup in sungem on Netra AC200 whenswitching interface up

[Greg KH]

2.6.28-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Ilkka Virta <itvirta@xxxxxx>

[ Upstream commit 71822faa3bc0af5dbf5e333a2d085f1ed7cd809f ]

From: Ilkka Virta <itvirta@xxxxxx>

In the lockup situation the driver seems to go off in an eternal storm
of interrupts right after calling request_irq(). It doesn't actually
do anything interesting in the interrupt handler. Since connecting the link
afterwards works, something later in initialization must fix this.

Looking at gem_do_start() and gem_open(), it seems that the only thing
done while opening the device after the request_irq(), is a call to
napi_enable().

I don't know what the ordering requirements are for the
initialization, but I boldly tried to move the napi_enable() call
inside gem_do_start() before the link state is checked and interrupts
subsequently enabled, and it seems to work for me. Doesn't even break
anything too obvious...

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/net/sungem.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/sungem.c
+++ b/drivers/net/sungem.c
@@ -2222,6 +2222,8 @@ static int gem_do_start(struct net_devic
 
 	gp->running = 1;
 
+	napi_enable(&gp->napi);
+
 	if (gp->lstate == link_up) {
 		netif_carrier_on(gp->dev);
 		gem_set_link_modes(gp);
@@ -2239,6 +2241,8 @@ static int gem_do_start(struct net_devic
 		spin_lock_irqsave(&gp->lock, flags);
 		spin_lock(&gp->tx_lock);
 
+		napi_disable(&gp->napi);
+
 		gp->running =  0;
 		gem_reset(gp);
 		gem_clean_rings(gp);
@@ -2339,8 +2343,6 @@ static int gem_open(struct net_device *d
 	if (!gp->asleep)
 		rc = gem_do_start(dev);
 	gp->opened = (rc == 0);
-	if (gp->opened)
-		napi_enable(&gp->napi);
 
 	mutex_unlock(&gp->pm_mutex);
 
@@ -2477,8 +2479,6 @@ static int gem_resume(struct pci_dev *pd
 
 		/* Re-attach net device */
 		netif_device_attach(dev);
-
-		napi_enable(&gp->napi);
 	}
 
 	spin_lock_irqsave(&gp->lock, flags);

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