em problems on SGI/AltixXE310

hi,
	this box is a dual 4 core intel/SGI, and it seems
that there is an intermittent problem: the em sometimes failes to initiatlize:
from dmesg:

em0: <Intel(R) PRO/1000 Network Connection Version - 6.5.3> port 0x2000-0x201f 
mem 0xd8a00000-0xd8a1ffff irq 18 at device 0.0 on pci4
em0: Hardware Initialization Failed
em0: Unable to initialize the hardware

this is from a session that it does work:

from pciconf -lvc:
em0_at_pci4:0:0:   class=0x020000 card=0x000015d9 chip=0x10968086 rev=0x01 
hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'PRO/1000 EB Network Connection'
    class      = network
    subclass   = ethernet
    cap 01[c8] = powerspec 2  supports D0 D3  current D0
    cap 05[d0] = MSI supports 1 message, 64 bit enabled with 1 message
    cap 10[e0] = PCI-Express 1 endpoint

from vmstat -i
irq256: em0                        16765         38

any ideas?
cheers,
	danny