[PATCH] fix MCA when shutting down tulip quad-NIC

[PATCH] fix MCA when shutting down tulip quad-NIC

[Olaf Hering]

From: andrew.patterson@hp.com

 https://bugzilla.novell.com/show_bug.cgi?id=SUSE39204

Shutting down the network causes an MCA because of an IO TLB error when
a DEC quad 10/100 card is in any slot.  This problem was originally seen
on an HP rx4640.


Signed-off-by: Olaf Hering <olaf@aepfle.de>

---

Andrew: Why is it tp->pdev instead of pdev?

 drivers/net/tulip/tulip_core.c |    1 +
 1 file changed, 1 insertion(+)

Index: b/drivers/net/tulip/tulip_core.c
===================================================================
--- a/drivers/net/tulip/tulip_core.c
+++ b/drivers/net/tulip/tulip_core.c
@@ -1798,6 +1798,7 @@ static void __devexit tulip_remove_one (
 		return;
 
 	tp = netdev_priv(dev);
+	pci_disable_device(tp->pdev);
 	unregister_netdev(dev);
 	pci_free_consistent (pdev,
 			     sizeof (struct tulip_rx_desc) * RX_RING_SIZE +

Re: [PATCH] fix MCA when shutting down tulip quad-NIC

[Valerie Henson]

On Tue, Apr 03, 2007 at 11:19:16PM +0200, Olaf Hering wrote:
> From: andrew.patterson@hp.com
> 
>  https://bugzilla.novell.com/show_bug.cgi?id=SUSE39204

Wow, registering for Novell's bugzilla is painful.  And in the end I
get "Access denied" on that bug.  Can you give us this information
some other way?

> Shutting down the network causes an MCA because of an IO TLB error when
> a DEC quad 10/100 card is in any slot.  This problem was originally seen
> on an HP rx4640.

I'm not clear on why pci_disable_device() would fix this bug.  Do you
have an explanation (or can copy one out of the bug report)?  I'm
hesitant to make even obviously correct changes to the tulip driver
without good evidence, given the incredible variety of buggy hardware
out there.

This looks to me like another iteration of the shutdown DMA/irq race
at first glance.  Grant has a patch for it; I'm working on one I
consider cleaner.

-VAL

> 
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
> 
> ---
> 
> Andrew: Why is it tp->pdev instead of pdev?

> 
>  drivers/net/tulip/tulip_core.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> Index: b/drivers/net/tulip/tulip_core.c
> ===================================================================
> --- a/drivers/net/tulip/tulip_core.c
> +++ b/drivers/net/tulip/tulip_core.c
> @@ -1798,6 +1798,7 @@ static void __devexit tulip_remove_one (
>  		return;
>  
>  	tp = netdev_priv(dev);
> +	pci_disable_device(tp->pdev);
>  	unregister_netdev(dev);
>  	pci_free_consistent (pdev,
>  			     sizeof (struct tulip_rx_desc) * RX_RING_SIZE +

Re: [PATCH] fix MCA when shutting down tulip quad-NIC

[Olaf Hering]

On Thu, Apr 05, Valerie Henson wrote:

> On Tue, Apr 03, 2007 at 11:19:16PM +0200, Olaf Hering wrote:
> > From: andrew.patterson@hp.com
> > 
> >  https://bugzilla.novell.com/show_bug.cgi?id=SUSE39204
> 
> Wow, registering for Novell's bugzilla is painful.  And in the end I
> get "Access denied" on that bug.  Can you give us this information
> some other way?

I did not see an easy way to make the bug public other than moving it to 
the openSuSE category.

> > Shutting down the network causes an MCA because of an IO TLB error when
> > a DEC quad 10/100 card is in any slot.  This problem was originally seen
> > on an HP rx4640.
> 
> I'm not clear on why pci_disable_device() would fix this bug.  Do you
> have an explanation (or can copy one out of the bug report)?  I'm
> hesitant to make even obviously correct changes to the tulip driver
> without good evidence, given the incredible variety of buggy hardware
> out there.

The comments in the bug do not have an detailed analysis.
One of the comments is:

...
Comment #1 From Andrew Patterson 2004-04-20 19:47:32 MST [reply]

1. ifdown the interfaces; then ifup them
2. do this in a loop from a script and it generally MCA's within 2 minutes.
...

The first version for 2.6.5 contained the pci_disable_device()
and a version which was commited to mainline:

http://git.kernel.org/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commitdiff;h=6379dd571265528f3911b9deafe2a29af2e71a2b

Later the patch contained just the pci_disable_device() call.

Andrew, does your testscript still fail in SLES10 or mainline?

> This looks to me like another iteration of the shutdown DMA/irq race
> at first glance.  Grant has a patch for it; I'm working on one I
> consider cleaner.

Thats likely the same issue.
http://www.linuxarkivet.se/mlists/linux-net/0409/msg00173.html