with that patch I don't see any difference at all in my setup.
So to be clear, with these commits on top of next-20160314, I still
get the hang during boot:
209afef6f0cd ARM: dts: rockchip: Add mdio node to ethernet node
2315acc6cf7f Revert "stmmac: first frame prep at the end of xmit routine"
b5e08e810c63 stmmac: fix tx prepare for normal desc
37c15a31d850 i2c: immediately mark ourselves as registered
4342eec3c5a2 Add linux-next specific files for 20160314
[ 27.521026] WARNING: CPU: 1 PID: 0 at net/sched/sch_generic.c:303
[ 27.529460] NETDEV WATCHDOG: eth0 (rk_gmac-dwmac): transmit queue 0 timed out