On Mon, Mar 26, 2007 at 09:47:25PM -0800, [EMAIL PROTECTED] wrote:
> From: Grant Grundler <[EMAIL PROTECTED]>
>
> IRQs are racing with tulip_down(). DMA can be restarted by the interrupt
> handler _after_ we call tulip_stop_rxtx() and the DMA buffers are unmapped.
> The result is an MCA (hard crash on ia64) because of an IO TLB miss. The
> long-term fix is to make the interrupt handler shutdown aware.
I don't know why this patch is surfacing again now.
I believe Val has addressed the problem with the "long-term" fix described.
thanks,
grant
> Signed-off-by: Grant Grundler <[EMAIL PROTECTED]>
> Acked-by: Valerie Henson <[EMAIL PROTECTED]>
> Cc: Jeff Garzik <[EMAIL PROTECTED]>
> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
> ---
>
> drivers/net/tulip/tulip_core.c | 31 +++++++++++++++++++++----------
> 1 file changed, 21 insertions(+), 10 deletions(-)
>
> diff -puN drivers/net/tulip/tulip_core.c~tulip-fix-shutdown-dma-irq-race
> drivers/net/tulip/tulip_core.c
> --- a/drivers/net/tulip/tulip_core.c~tulip-fix-shutdown-dma-irq-race
> +++ a/drivers/net/tulip/tulip_core.c
> @@ -734,23 +734,36 @@ static void tulip_down (struct net_devic
> #endif
> spin_lock_irqsave (&tp->lock, flags);
>
> + /*
> + FIXME: We should really add a shutdown-in-progress flag and
> + check it in the interrupt handler to see whether we should
> + reenable DMA or not. The preferred ordering here would be:
> +
> + stop DMA engine
> + disable interrupts
> + remove DMA resources
> + free_irq()
> +
> + The below works but is non-obvious and doesn't match the
> + ordering of bring-up. -VAL
> + */
> +
> /* Disable interrupts by clearing the interrupt mask. */
> iowrite32 (0x00000000, ioaddr + CSR7);
> + ioread32 (ioaddr + CSR7); /* flush posted write */
>
> - /* Stop the Tx and Rx processes. */
> - tulip_stop_rxtx(tp);
> + spin_unlock_irqrestore (&tp->lock, flags);
>
> - /* prepare receive buffers */
> - tulip_refill_rx(dev);
> + free_irq (dev->irq, dev); /* no more races after this */
> + tulip_stop_rxtx(tp); /* Stop DMA */
>
> - /* release any unconsumed transmit buffers */
> - tulip_clean_tx_ring(tp);
> + /* Put driver back into the state we start with */
> + tulip_refill_rx(dev); /* prepare RX buffers */
> + tulip_clean_tx_ring(tp); /* clean up unsent TX buffers */
>
> if (ioread32 (ioaddr + CSR6) != 0xffffffff)
> tp->stats.rx_missed_errors += ioread32 (ioaddr + CSR8) & 0xffff;
>
> - spin_unlock_irqrestore (&tp->lock, flags);
> -
> init_timer(&tp->timer);
> tp->timer.data = (unsigned long)dev;
> tp->timer.function = tulip_tbl[tp->chip_id].media_timer;
> @@ -776,7 +789,6 @@ static int tulip_close (struct net_devic
> printk (KERN_DEBUG "%s: Shutting down ethercard, status was
> %2.2x.\n",
> dev->name, ioread32 (ioaddr + CSR5));
>
> - free_irq (dev->irq, dev);
>
> /* Free all the skbuffs in the Rx queue. */
> for (i = 0; i < RX_RING_SIZE; i++) {
> @@ -1747,7 +1759,6 @@ static int tulip_suspend (struct pci_dev
> tulip_down(dev);
>
> netif_device_detach(dev);
> - free_irq(dev->irq, dev);
>
> pci_save_state(pdev);
> pci_disable_device(pdev);
> _
-
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