Subject: Re: [PATCH 2.6.30-rc4] r8169: avoid losing MSI interrupts

From: [email-masked] (Eric W. Biederman)
Date: Sat, 22 Aug 2009 04:48:52 -0700

David Dillow <[email-masked]> writes:

>
> Re-looking at the code, I'd guess that some IRQ status line is getting
> stuck high, but I don't see why -- we should acknowledge all outstanding
> interrupts each time through the loop, whether we care about them or
> not.
>
> Could reproduce a problem with the following patch applied, and send the
> full dmesg, please?

Here is what I get.

r8169 screaming irq status 00000085 mask 0000ffff event 0000803f napi 0000001d

Eric

> diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
> index b82780d..46cb05a 100644
> --- a/drivers/net/r8169.c
> +++ b/drivers/net/r8169.c
> @@ -3556,6 +3556,7 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
>  	void __iomem *ioaddr = tp->mmio_addr;
>  	int handled = 0;
>  	int status;
> +	int count = 0;
>  
>  	/* loop handling interrupts until we have no new ones or
>  	 * we hit a invalid/hotplug case.
> @@ -3564,6 +3565,15 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
>  	while (status && status != 0xffff) {
>  		handled = 1;
>  
> +		if (count++ > 100) {
> +			printk_once("r8169 screaming irq status %08x "
> +				"mask %08x event %08x napi %08x\n",
> +				status, tp->intr_mask, tp->intr_event,
> +				tp->napi_event);
> +			break;
> +		}
> +
> +
>  		/* Handle all of the error cases first. These will reset
>  		 * the chip, so just exit the loop.
>  		 */