From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <shemminger@vyatta.com>
Subject: Re: [PATCH] ibm_newemac: emac_close() needs to call
 netif_carrier_off()
Date: Wed, 19 Aug 2009 14:11:36 -0700
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Cc: benh@kernel.crashing.org, davem@davemloft.net,
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To: Petri Gynther <pgynther@google.com>
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On Wed, 19 Aug 2009 14:00:00 -0700 (PDT)
Petri Gynther <pgynther@google.com> wrote:

> When ibm_newemac netdev instance is shutdown with "ifconfig down",
> the netdev interface does not go properly down. netif_carrier_ok()
> keeps returning TRUE even after "ifconfig down".
> 
> The problem can be seen when ibm_newemac instances are slaves of
> a bonding interface. The bonding interface code uses netif_carrier_ok()
> to determine the link status of its slaves. When ibm_newemac slave is
> shutdown with "ifconfig down", the bonding interface won't detect any
> link status change because netif_carrier_ok() keeps returning TRUE.

Bonding should be testing for netif_running() && netif_carrier_ok().

In many devices state of carrier is undefined when device is down.