netdev - Re: niu interface automatically goes up then down

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Date:	Thu, 10 Jan 2013 12:27:11 +1100
From:	Julian Calaby <julian.calaby@...il.com>
To:	Jan Engelhardt <jengelh@...i.de>
Cc:	Linux Networking Developer Mailing List <netdev@...r.kernel.org>,
	sparclinux@...r.kernel.org
Subject: Re: niu interface automatically goes up then down

Hi Jan,

Thanks for the answers.

On Thu, Jan 10, 2013 at 11:55 AM, Jan Engelhardt <jengelh@...i.de> wrote:
>
> On Thursday 2013-01-10 01:24, Julian Calaby wrote:
>>>
>>> The interface itself is marked UP, and is part of a bridge,
>>> if that matters. The kernel version is 3.7.1 on sparc64.
>>>
>>> 6: eth4: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500
>>> qdisc mq master br0 state DOWN qlen 1000
>>>     link/ether 00:21:28:71:32:5a brd ff:ff:ff:ff:ff:ff
>>>     inet6 fe80::221:28ff:fe71:325a/64 scope link
>>>        valid_lft forever preferred_lft forever
>>
>>That is rather odd. Is this particular interface connected to anything
>>that could be causing this?
>
> Nope, there is nothing connected to eth4. UP indicates that
> I had issue `ip link set dev eth4 up`.

I assumed that from the "NO-CARRIER" status, but I had to check: for
all I know it's some sort of failover connection and is hooked up to a
disabled port on a different switch.

>>> At the same time, eth5, to which a cable+machine _is_ connected,
>>> randomly goes out. At first I thought it might be the connected peer,
>>> but seeing that eth4 randomly does a up-down cycle leads me to assume
>>> that niu is doing a cycle here rather than the peer.
>>>
>>> [ 3839.724721] niu 0000:10:00.1 eth5: Link is down
>>> [ 3839.725077] br0: port 5(eth5) entered disabled state
>>> [ 3840.725016] niu 0000:10:00.1 eth5: Link is up at 100Mbit/sec, half duplex
>>> [ 3840.725195] br0: port 5(eth5) entered forwarding state
>>> [ 3840.725327] br0: port 5(eth5) entered forwarding state
>>> [ 3855.762171] br0: port 5(eth5) entered forwarding state
>>
>>Again, could it be the device at the end of the link?
>>Out of curiosity, why do you have these two ports bridged together and
>>what is the purpose of this configuration?
>
> Nobody expects the... lack of a switch. And since there are
> plenty of ports in the machine anyway, might as well use them as a
> software switch as an intermediate solution.

True that. I have an overabundance of PCI network cards and have built
temporary servers with two of them bridged together so I'm not
stealing a port that might be needed.

> eth0 through eth3 is a quad-port e1000e.
> eth4 through eth7 is the quad-port niu.
>
> The e1000e ports don't flake out at all, therefore I rate
> the peer(s) being at fault with a very low probability.

Makes sense.

> The issue is not pressing, since it's just service processors
> which are connected.

Ok, I'm guessing that this is production so heavy debugging isn't
going to happen.

I'm out of ideas. Tag?

Thanks,

-- 
Julian Calaby

Email: julian.calaby@...il.com
Profile: http://www.google.com/profiles/julian.calaby/
.Plan: http://sites.google.com/site/juliancalaby/
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