sungem: Soft lockup in sungem on Netra AC200 when switching interface up

[ Upstream commit 71822faa3bc0af5dbf5e333a2d085f1ed7cd809f ]

From: Ilkka Virta <itvirta@iki.fi>

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@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/net/sungem.c b/drivers/net/sungem.c
index fed7eba65ead6268e292eddc66c73905d8e263c7..cb9e3f535c58f125d308173cc9e48d71dc649d3a 100644 (file)
--- a/drivers/net/sungem.c
+++ b/drivers/net/sungem.c
@@ -2222,6 +2222,8 @@ static int gem_do_start(struct net_device *dev)
 
        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_device *dev)
                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 *dev)
        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 *pdev)
 
                /* Re-attach net device */
                netif_device_attach(dev);
-
-               napi_enable(&gp->napi);
        }
 
        spin_lock_irqsave(&gp->lock, flags);