kern/148004: Inconsistent networking with em driver on FreeBSD 8.0-p2

[Bill Clark]

>Number:         148004
>Category:       kern
>Synopsis:       Inconsistent networking with em driver on FreeBSD 8.0-p2
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Jun 20 05:20:02 UTC 2010
>Closed-Date:
>Last-Modified:
>Originator:     Bill Clark
>Release:        FreeBSD 8.0-p2
>Organization:
Before It's News
>Environment:
FreeBSD c4.beforeitsnews.com 8.0-RELEASE-p2 FreeBSD 8.0-RELEASE-p2 #0: Fri Jan  8 06:01:44 GMT 2010     root at b1.beforeitsnews.com:/usr/obj/usr/src/sys/GENERIC  i386

>Description:
Machine with dual Intel(R) PRO/1000 Network Connection using em driver, updated to latest version 6.9.21 from Intel website (initially 6.9.14 with same problem) will connect fine to one (older) switch but completely non-functional (despite link lights) on another (newer) switch.  There's nothing wrong with the switch, since a dozen other FreeBSD machines (using bge or fxp) all work fine on it.  I've looked through many similar problem reports online and none of the diagnostic steps or fixes have helped.  No errors of any kind are reported.. the networking simply does not work, as if the interface were down.  Changing to the other switch, it works perfectly.  I unfortunately do not have the details about what models the two different switches are, as they're in a remote datacenter and my remote assistant gave up in frustration after the millionth time I had him juggle connections around.

dmesg:

em0: <Intel(R) PRO/1000 Network Connection 6.9.21> port 0xcc00-0xcc3f mem 0xfc9e0000-0xfc9fffff irq 74 at device 1.0 on pci5
em0: [FILTER]
em0: Ethernet address: 00:30:48:85:b0:44

sysctl -a:

dev.em.0.%desc: Intel(R) PRO/1000 Network Connection 6.9.21
dev.em.0.%driver: em
dev.em.0.%location: slot=1 function=0
dev.em.0.%pnpinfo: vendor=0x8086 device=0x1076 subvendor=0x15d9 subdevice=0x1076 class=0x020000
dev.em.0.%parent: pci5
dev.em.0.debug: -1
dev.em.0.stats: -1
dev.em.0.rx_int_delay: 0
dev.em.0.tx_int_delay: 66
dev.em.0.rx_abs_int_delay: 66
dev.em.0.tx_abs_int_delay: 66
dev.em.0.rx_processing_limit: 100

ifconfig -a:

em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=389b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_UCAST,WOL_MCAST,WOL_MAGIC>
        ether 00:30:48:85:b0:44
        inet 10.0.0.104 netmask 0xffffff00 broadcast 10.0.0.255
        media: Ethernet autoselect (1000baseT <full-duplex>)
        status: active

netstat -rn:

Destination        Gateway            Flags    Refs      Use  Netif Expire
10.0.0.0/24        link#1             U           0        8    em0

>How-To-Repeat:

>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: