I've recently built my first PC and got it all working (yay!) except for the USB 3.0 ports. I don't think any of the USB 3.0 ones are working, there are some in the MB/back and also a couple at the front, I did plug in the USB 3.0 wire from the case to the mb, and made sure the USB 3.0 option is enabled in BIOS. I can't update the mb drivers as there are only options for windows on the msi site. MB is MSI 970 Gaming.
If I go into BIOS, I can see the devices I have plugged into the USB 3.0's, but if I try to see them through the command line once booted, they aren't there.
I had the same problem. Resolved it by adding in
sudo update-grub, reboot and voilà!
Just to clarify, I'd like to get to the point of plugging in a USB device (mainly into the front ports) and have them recognized. I'm not too concerned about whether they function as USB version 2 or 3 right now, so long as they work.