On Monday 28 May 2007 16:12:12 Maximilian Engelhardt wrote:

On Monday 28 May 2007, Michael Buesch wrote:

quoted

Can you also test the following patch?
I think there's a bug in b44 that is doesn't properly discard
shared IRQs, so it might possibly generate a NAPI storm, dunno.
Worth a try.

Index: linux-2.6.22-rc3/drivers/net/b44.c
===================================================================

--- linux-2.6.22-rc3.orig/drivers/net/b44.c	2007-05-27 23:01:44.000000000
+0200 +++ linux-2.6.22-rc3/drivers/net/b44.c	2007-05-28 12:48:27.000000000
+0200 @@ -911,6 +911,8 @@ static irqreturn_t b44_interrupt(int irq
 	spin_lock(&bp->lock);

 	istat = br32(bp, B44_ISTAT);
+	if (istat == 0xFFFFFFFF)
+		goto out; /* Shared IRQ not for us */
 	imask = br32(bp, B44_IMASK);

 	/* The interrupt mask register controls which interrupt bits

@@ -942,6 +944,7 @@ irq_ack:
 		bw32(bp, B44_ISTAT, istat);
 		br32(bp, B44_ISTAT);
 	}
+out:
 	spin_unlock(&bp->lock);
 	return IRQ_RETVAL(handled);
 }

I did try this patch on a affected kernel, but I didn't notice any big 
difference. Perhaps the kernel is a bit less slow during the test, but It's 
hard to tell.

Ok, but anyway. I think this is a bug and needs to be fixed this way. Gary?

-- 
Greetings Michael.