[PATCH 0/1] smsc9420: fix interrupt signalling test failures

[PATCH 0/1] smsc9420: fix interrupt signalling test failures

[Steve Glendinning]

Hi David,

One important driver fix for you, please apply to 2.6.29 as the driver 
will fail to initialise on some platforms without it.

I'm amazed this test ever passed, I guess it's because I'm on a fast
SMP machine which managed to beat the race.

Steve Glendinning (1):
  smsc9420: fix interrupt signalling test failures

 drivers/net/smsc9420.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

[PATCH 1/1] smsc9420: fix interrupt signalling test failures

[Steve Glendinning]

smsc9420 performs an interrupt signalling test when the interface is
brought up.  The current code mistakenly sets its test flag to false
AFTER enabling the software interrupt source, making failure quite
likely.

This patch changes the code to set the test flag BEFORE enabling
interrupts. I've also removed an smp_wmb because the following spinlock
provides an implicit memory barrier.

Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>
---
 drivers/net/smsc9420.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/net/smsc9420.c b/drivers/net/smsc9420.c
index c14a4c6..d801900 100644
--- a/drivers/net/smsc9420.c
+++ b/drivers/net/smsc9420.c
@@ -1378,6 +1378,7 @@ static int smsc9420_open(struct net_device *dev)
 
 	/* test the IRQ connection to the ISR */
 	smsc_dbg(IFUP, "Testing ISR using IRQ %d", dev->irq);
+	pd->software_irq_signal = false;
 
 	spin_lock_irqsave(&pd->int_lock, flags);
 	/* configure interrupt deassertion timer and enable interrupts */
@@ -1393,8 +1394,6 @@ static int smsc9420_open(struct net_device *dev)
 	smsc9420_pci_flush_write(pd);
 
 	timeout = 1000;
-	pd->software_irq_signal = false;
-	smp_wmb();
 	while (timeout--) {
 		if (pd->software_irq_signal)
 			break;
-- 
1.6.0.6

Re: [PATCH 1/1] smsc9420: fix interrupt signalling test failures

[David Miller]

From: Steve Glendinning <steve.glendinning@smsc.com>
Date: Thu, 29 Jan 2009 16:39:23 +0000

> smsc9420 performs an interrupt signalling test when the interface is
> brought up.  The current code mistakenly sets its test flag to false
> AFTER enabling the software interrupt source, making failure quite
> likely.
> 
> This patch changes the code to set the test flag BEFORE enabling
> interrupts. I've also removed an smp_wmb because the following spinlock
> provides an implicit memory barrier.
> 
> Signed-off-by: Steve Glendinning <steve.glendinning@smsc.com>

Applied, thanks Steve.