em0: watchdog timeout -- resetting

[Lev Serebryakov]

Hello, .

System:
FreeBSD xxx.xxx.xx 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #0: Fri Dec  5 20:37:31 MSK 2008     lev at xxx.xxx.xx:/usr/obj/usr/src/sys/BLOB  amd64

Hardware:
% dmesg | grep em0
em0: <Intel(R) PRO/1000 Network Connection 6.9.6> port 0xe880-0xe89f mem 0xfea40000-0xfea5ffff,0xfea7a000-0xfea7afff irq 20 at device 25.0 on pci0
em0: [FILTER]
em0: Ethernet address: 00:1e:8c:75:03:0d
% pciconf -lv | grep
em0 at pci0:0:25:0:        class=0x020000 card=0x82681043 chip=0x10bd8086 rev=0x02 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = '82566DM-2 Gigabit Network Connection'
    class      = network
    subclass   = ethernet
% ifconfig em0
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 9014
        options=19b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4>
        ether 00:1e:8c:75:03:0d
        inet 192.168.134.3 netmask 0xffffff00 broadcast 192.168.134.255
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active
%

Hardware is ASUS P5E-VM DO motherboard with integrated controller.

Network is connected to HP ProCurce 1400-8G gigabit switch.

I'm getting "em0: watchdog timeout -- resetting" (and all connections
are lost!) very often. If here are network load it could be every 5
minutes sometimes... For example:

==============================================================
Dec  5 22:01:39 blob kernel: em0: watchdog timeout -- resetting
Dec  5 22:01:39 blob kernel: em0: link state changed to DOWN
Dec  5 22:01:42 blob kernel: em0: link state changed to UP
Dec  5 22:01:56 blob kernel: em0: watchdog timeout -- resetting
Dec  5 22:01:56 blob kernel: em0: link state changed to DOWN
Dec  5 22:01:59 blob kernel: em0: link state changed to UP
Dec  5 22:02:01 blob kernel: em0: link state changed to DOWN
Dec  5 22:02:03 blob kernel: em0: link state changed to UP
Dec  5 22:06:07 blob kernel: em0: watchdog timeout -- resetting
Dec  5 22:06:07 blob kernel: em0: link state changed to DOWN
Dec  5 22:06:09 blob kernel: em0: link state changed to UP
Dec  5 22:07:18 blob kernel: em0: watchdog timeout -- resetting
Dec  5 22:07:18 blob kernel: em0: link state changed to DOWN
Dec  5 22:07:24 blob kernel: em0: link state changed to UP
==============================================================

 I could provide any additional information.

-- 
// Black Lion AKA Lev Serebryakov <lev at FreeBSD.org>