em(4) on FreeBSD is sometimes annoying

Markus Vervier markus at vervier.info
Fri Aug 8 17:56:45 UTC 2008

Jack Vogel schrieb:
> "me too" 's are of little help. Please elaborate on your "exact same",  since
> each person's perception will be slightly different.
Hi Jack,

maybe read it like: Thinkpad X60 1706GMG affected too, so the problem is 
not specific to Martins machine.

I can write the same steps to reproduce the behaviour as Martin here:

Once again, steps to reproduce this behavior:
1) Power the laptop OFF. Really OFF, I mean. No reboots!
2) Detach the cable from NIC.
3) Boot FreeBSD. Let it pass the DHCP phase (ifconfig_em0="DHCP") until
login appears.
4) Attach the cable to the NIC.
5) Voila... no link.

My perception is that if the em driver gets loaded without a cable being 
plugged in, no link can be established.
I can workaround the problem when em was not build into the kernel, by 
unloading the em-kmod and reloading it
again with the cable plugged in. If the cable is not plugged in the 
interface will always stay in state "no carrier".
The NIC works fine under Windows / Linux on the same machine.


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