Date: Thu, 29 Mar 2007 10:59:00 +1200 From: Andrew Thompson <thompsa@freebsd.org> To: Jeremy Chadwick <koitsu@FreeBSD.org> Cc: freebsd-stable@freebsd.org Subject: Re: em(4) losing link when if_bridge(4) addm/deletem are used Message-ID: <20070328225900.GB80375@heff.fud.org.nz> In-Reply-To: <20070328223045.GA84408@icarus.home.lan> References: <20070328033327.GA65649@icarus.home.lan> <20070328213709.GA80375@heff.fud.org.nz> <20070328223045.GA84408@icarus.home.lan>
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On Wed, Mar 28, 2007 at 03:30:45PM -0700, Jeremy Chadwick wrote: > On Thu, Mar 29, 2007 at 09:37:09AM +1200, Andrew Thompson wrote: > > On Tue, Mar 27, 2007 at 08:33:27PM -0700, Jeremy Chadwick wrote: > > > In the midst of the madness, I found that when doing either of the > > > following commands... > > > > > > ifconfig bridge0 addm em1 > > > ifconfig bridge0 deletem em1 > > > > > > ...I see the entire em1 interface completely reset, bringing down link, > > > then up again shortly after. The logs on my switch also confirm this. > > > > > The only other thing the bridge does to the interface when removing it > > is to reinstate IFCAP_TXCSUM, which is disabled when the interface is > > bridged. If you manually toggle this with ifconfig do you get the same > > result? > > Bingo. > > medusa# ifconfig em1 -txcsum > medusa# ifconfig em1 > em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > options=8<VLAN_MTU> > inet 10.0.0.2 netmask 0xffffff00 broadcast 10.0.0.255 > ether 00:30:48:71:60:6b > media: Ethernet autoselect > status: no carrier > medusa# grep em1 /var/log/messages > Mar 28 15:29:34 medusa kernel: em1: link state changed to DOWN > Mar 28 15:29:36 medusa kernel: em1: link state changed to UP As a workaround you could remove txcsum at boot, then the bridge will not toggle it. Long term you could prod the em(4) maintainer to see if this can be resolved. Andrew
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