Pixhawk (on 3.7.1 ) power supply question

Hardware Planes
1

I have fitted a Pixhawk in my Skywalker X5. One question I cannot find a definitive answer to is do I need to supply power direct to the servo rail as well as power socket?

The servos seem to work fine without any power to the servo rail but I don’t want to risk a brownout.

2

This seems to be a duplicate question. See:
http://discuss.ardupilot.org/t/do-i-need-to-power-servo-rail/13238