The Ethernet link between my ZCU102 board and a host machine at 100M/Full does not work. The link keeps going up and down:
In PetaLinux 2015.4, 2016.1 and 2016.2, dynamic speed switching is not possible. Only the default speed of 1G is supported.
This is NOT a silicon or board limitation but a Linux infrastructure (to enable dynamic speed switching) being under development and not ready yet.
Configure the host machine to "Auto-negotiation" or "1G/Full".
This is (tentatively) planned to be fixed for the 2016.3 release.