Re: b44: regression in 2.6.22 (resend)

Maximilian Engelhardt
2007-05-28T14:12:31Z

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On Monday 28 May 2007, Michael Buesch wrote:
> 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.

Maxi

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