[Macchiato] SFP+ ports - any config needed?

[Baruch Siach]

Hi Steve,

Steve McIntyre writes:
> Thanks for your support!
>
> On Tue, Dec 18, 2018 at 05:51:54PM +0200, Baruch Siach wrote:
>>Steve McIntyre writes:
>>> On Sun, Dec 16, 2018 at 01:21:30PM +0200, Baruch Siach wrote:
>>>>Steve McIntyre writes:
>>>>> I've just got a new switch with some 10G SFP+ ports on it, and I'm
>>>>> trying to use it with my macchiatobin, with some simple SFP+ direct
>>>>> attach cables.
>>>>>
>>>>> Naively, I just plugged things together and hoped for the best. *grin*
>>>>> But I don't seem to be getting any link on my cable. I don't see any
>>>>> obvious way of configuring the two 10G ports to use the SFP+ cages
>>>>> rather than the RJ45 TP connectors. Can somebody tell me what I'm
>>>>> missing please? Marcin?
>>>>
>>>>Which kernel version are you using?
>>>
>>> Debian's 4.18 backports kernel, which is "4.18.6-1~bpo9+1".
>>>
>>>>Do you have CONFIG_SFP and CONFIG_MARVELL_10G_PHY enabled?
>>>
>>> Yup.
>>
>>Then you should at least see the sfp driver messages.
>
> So I've found the problem (I think!) - in the Debian kernel we have
> CONFIG_MARVELL_10G_PHY=m and AFAICS there's nothing triggering
> autoloading of the module. Without it, things just don't work. Forcing
> the system to load it at boot time on the 4.18 backports kernel (via
> listing in /etc/modules) makes things work for me:
>
> [   14.576557] mvpp2 f2000000.ethernet eth0: PHY [f212a600.mdio-mii:00] driver [mv88x3310]
> [   14.596758] mvpp2 f2000000.ethernet eth0: configuring for phy/10gbase-kr link mode
> [   14.605163] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
> [   15.617114] mvpp2 f2000000.ethernet eth0: Link is Up - 10Gbps/Full - flow control off
> [   15.625016] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
>
> It clearly needs to be loaded before mvpp2, but there's something more
> awkward here too. If I unload mvpp2 then modprobe marvell10g and mvpp2
> I still don't get any traffic on the SFP+. There's a dependency order
> that's not obvious, to me at least! Should the mvpp2 driver be
> declaring a dependency on marvell10g here?

I don't think so. The Armada 8K MAC can work with other PHYs. The kernel
messages indicate that the MAC correctly identified the PHY (mv88x3310).
so the right kernel module should have been loaded. Not sure what is
missing here.

> I'm also trying a current build of 4.20.0-rc7 using the same kernel
> config inherited from Debian, and I see the same behaviour as with
> 4.18.6. So your fix in 01b3fd5ac97c wasn't needed for me, at least.

Maybe that's because your kernel is missing commit 24205e4e62dd ("net:
phy: phylink: fix SFP interface autodetection") from the -stable
linux-4.18.y branch (upstream commit 7e41837527). It only appeared in
v4.18.15. Without this patch the PHY mode set in the device-tree takes
over.

> I'm still seeing oddness from ethtool, with both kernels. With the
> SFP+ plugged in and running I'm seeing:
>
> root at mjolnir:/home/steve# ethtool eth0
> Settings for eth0:
>         Supported ports: [ TP ]
>         Supported link modes:   10baseT/Half 10baseT/Full
>                                 100baseT/Half 100baseT/Full
>                                 1000baseT/Full
>                                 10000baseT/Full
>         Supported pause frame use: Symmetric Receive-only
>         Supports auto-negotiation: Yes
>         Advertised link modes:  10baseT/Half 10baseT/Full
>                                 100baseT/Half 100baseT/Full
>                                 1000baseT/Full
>                                 10000baseT/Full
>         Advertised pause frame use: Symmetric Receive-only
>         Advertised auto-negotiation: Yes
>         Speed: 10000Mb/s
>         Duplex: Full
>         Port: MII
>         PHYAD: 0
>         Transceiver: internal
>         Auto-negotiation: on
>         Link detected: yes
>
> so I'm guessing there's something not quite right in the mvpp2 ethtool
> backend?

What is it that you find odd in this output?

baruch

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