AMD System fresh install , Only USB 3 working (IOMMU?)

Question

I fresh installed Ubuntu 16.04 on my AMD machine

• CPU: AMD FX 8350
• MOBO: Gigabyte 970A-UD3P (AM3+)

Problem is that when the OS first booted both my KB and mouse were not working , until i switched to USB3 ports..

I read some other kinda similar issues that had to do with IOMMU and some people activating it in the BIOS , but when i did that everything went wrong , and USB3 ports were not(!) working.

I rolled back to my initial setup and came here for help..

Any ideas?

Answer 1

I was getting errors on a fresh install of Ubuntu 16.04 on my PC

• CPU: FX 6300
• MOBO: GA 970A-DS3P

Errors were like this:

usb 5-1: device descriptor read/64, error -32
usb 5-1: device descriptor read/64, error -110
usb 5-1: device not accepting address 4, error -32
usb 5-1: device not accepting address 4, error -110

Then I tried this.

First, enable IOMMU in the BIOS by restarting your computer and pressing delete to enter the BIOS (3.0 ports won't work after this step, don't worry, they will soon)

Plug your USB mouse and keyboard in USB 2.0 ports.

Save and exit the BIOS

Then In Ubuntu:

Press Ctrl+Alt+T to open up a terminal

Run the following command:

sudo nano /etc/default/grub

Only edit the empty quotes in this line to read: GRUB_CMDLINE_LINUX="iommu=soft"

Save changes to grub and exit

Open up a new terminal with Ctrl+Alt+T,

Run the following command: sudo update-grub

Exit the terminal

Restart your computer, press delete to get back into the BIOS

Disable IOMMU, load optimized defaults and restart.

It's done!

USB 2.0 and USB 3.0 should work now in Ubuntu, and disabling IOMMU in BIOS may also help speed up your boot.