I've been running my 2PAC on a Raspberry Pi 3 but decided to invest in a powered USB hub. I have connected a HDD to the hub (it works fine) but cgminer is unable to find my 2PAC when it's connected to the hub. When I plug the 2PAC into the Rasp's USB ports, it's OK. How do I get cgminer to find the 2PAC plugged into the hub? Thanks!
In short: only some USB 3 powered hubs can be directly linked to rasp pi (Superbpag is one such known example where it works; USB 2 powered Plugable also works directly with pi, not sure it it is enough for 2pacs).
most USB 3 hubs would not work by themselves (it includes Anker), however, don't despair, there is a simple runaround: use non-powered simple usb hub (like USB2 Sabrent for around $6), connect it to rasp pi, then connect your powered hub to Sabrent, then it should work, providing that you push the button on Sabrent to activate the slot (it should shine blue).
TL;DR either return your USB 3 hub (non-Superbpag) and get Superbpag OR get a non-powered hub like Sabrent and use it as a bridge.