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

[Peter S. <p.s...@gm...>]

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,  but 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?

> When you bring down the interface on the other end - if you still see the 
> LINK LED of the NIC to be lit then the driver is reporting the status correctly.

When the DA copper cable is connected, the LED is always on on both machines. 
Even if the interface is turned down in Linux.
When I switch to fibre, the LED is off on both machines as soon as I set one interface down.

Thank you very much for your answer!

> Thanks,
> Emil
>