GA-970A-DS3P revision 1 no usb 3.0
Enabling iommu in the bios will fix the Ethernet issue and make the usb 2.0 ports work for Gigabyte 970 chipset board GA-970A-DS3P rev 1.0, but usb 3.0 ports will no longer work on the back of the motherboard or from the internal 20 pin connector for the front panel. I have tried Ubuntu 12.04 LTS and 14.04 with the same result. If there is anyone else in the same boat please post up.
Re: GA-970A-DS3P revision 1 no usb 3.0
run the following command: gksudo gedit /etc/default/grub
Edit the empty quotes in this line to read: GRUB_CMDLINE_LINUX="iommu=soft"
save changes to grub
ctrl+alt+t to open up a terminal
Disable iommu in bios, load optimized defaults and restart.
usb, 2.0 usb 3.0 and networking all work now in Ubuntu, and disabling iommu in bios helps prevent windows freezes that was occurring if you are running a dual boot environment.
If the above post helps at least one person I am happy.