DP-3 output doesn't work on NVS 510 (Kepler, NVE7, GK107) card.

As soon as I load nouveau, third output becomes blank. All other outputs,
including the fourth (last one) works fine.

xorg properly detects monitor and its modes on buggy videoout.
xrandr shows monitor as connected and enabled.
I see no errors anywhere.

I've tested only compiled debian kernels 3.10 -- 3.14

Let me know what output should I provide or how could I help to solve this bug.