Re: [E1000-devel] IXGBE X520-DA2 82599ES SFP+ DA Is carrier detection working?

[Tantilov, E. S <emi...@in...>]

>-----Original Message-----
>From: Peter Schmitt [mailto:p.s...@gm...]
>Sent: Wednesday, December 09, 2015 12:18 AM
>To: Tantilov, Emil S; e10...@li...
>Subject: Re: [E1000-devel] IXGBE X520-DA2 82599ES SFP+ DA Is carrier
>detection working?
>
>Hi,
>
>On 08.12.2015 18:42, Tantilov, Emil S wrote:
>
>>> -----Original Message-----
>>> From: Peter Schmitt [mailto:p.s...@gm...]
>>> Sent: Tuesday, December 08, 2015 8:02 AM
>>> To: e10...@li...
>>> Subject: [E1000-devel] IXGBE X520-DA2 82599ES SFP+ DA Is carrier
>detection
>>> working?
>>>
>>> Hi everyone,
>>>
>>> I am connecting two boxes using X520-DA2 82599ES 10-Gigabit SFI/SFP+
>>> NICs and the ixgbe
>>> driver in Linux. Those cards have two SFP+ ports. If I connect a Direct
>>> Attach Copper cable, the carrier detection does not work correctly. As
>>> soon as
>>> the device in Linux is up, there is a carrier and it doesn't matter if
>the
>>> device on the other box is up or down.
>> Is the device and driver on the "other box" the same?
>
>Yes, the NICs are identical and the software is also the same. The same
>Linux kernel and ixgbe versions:
>Linux 4.1.13 x86_64 and ixgbe 4.0.1-k.
>
>
>>> If I use Fibre and an SR module, the carrier detection works flawless.
>The
>>> interface detects a carrier if the interface on the other box is up and
>>> doesn't if the interface is down.
>> The driver shuts off the laser for SFP+ modules and can power down the
>PHY
>> on copper parts,  b
ut that probably won't happen on DA copper cable.
>
>Ok, so it is a hardware problem? The driver cannot enable proper carrier
>detection when using DA copper cables?

There is no problem with carrier detection - if the Link LED is on that
means that the ports have link. Bringing down the interface does not 
always result in losing link. For example the driver will not shut down
the PHY or disable the lasers if the interface supports and is configured
for WOL.

Thanks,
Emil