From: Antoine Tenart <redacted>
Date: Fri,  4 May 2018 15:56:30 +0200

Also as the SFP cages on both DB boards can be considered as non-wired,
the SFP code was reworked to really support when some pins of the SFP
cage aren't described in the device tree. Also a warning was added when
no Tx disable pin is available. (Patches 1-3).

I guess there is still discussion about whether fixed-link should be
used for this instead of SFP.