em(4) on FreeBSD is sometimes annoying

Jack Vogel jfvogel at gmail.com
Fri Aug 1 16:24:56 UTC 2008

If the poster gives me EXACT hardware list I will see about repro'ing the
problem inhouse. We do not do much of anything with laptops but I
will see. Oh and a pciconf would help too.


On Fri, Aug 1, 2008 at 7:43 AM, Robert Watson <rwatson at freebsd.org> wrote:
> On Fri, 1 Aug 2008, Martin wrote:
>> I don't remember anymore when I reported it the first time. I think it was
>> around 4.x or something like that. The em(4) bug is still there after years.
>> Hasn't anyone really noticed yet that em(4) only appears when you boot
>> FreeBSD with the interface physically attached to a switch for example? If
>> you attach it later, after boot up, the interface won't power up and appear
>> in the interface list (ifconfig)?
> The card range supported by the if_em driver is huge, so it wouldn't be
> surprising if this is a hardware bug affecting a relatively narrow line of
> parts.  I've added Jack Vogel to the CC line, as he's the Intel developer
> responsible for maintaining our if_em driver.  I don't promise he can help
> either, but it's worth a try :-).
> Robert
>> Steps to reproduce:
>> 1) Switch your PC/laptop off. Really OFF, no reboot.
>> 2) Disconnect the em(4) NIC from your switch.
>> 3) Boot FreeBSD.
>> 4) Plug in the ethernet cable.
>> 5) Tataa! All leds at the NIC stay off. You won't be able to use em(4)
>> unless you reboot your machine.
>> Something is not being initialized properly on em(4) devices, it seems.
>> I have had 3 of 3 em(4) NICs so far, where this bug shows up. And it's
>> extremely annoying on Thinkpads, when you just want to plug in your
>> laptop somewhere.
>> --
>> Martin

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