Comment 19 for bug 1313279

I'm running ubuntu 18.04 and have the same problems with USB 3.0.
The ONLY way to get it to work at all ever is to turn iommu off in the bios
and use iommu=soft as kernel parameter (as is described as the "solution"
on many forums) AND I need to have certain device plugged into USB and/or
something else magical that I didn't pin point.

Anyway, once USB 3 works, it keeps working until I turn off a device
(Valve Index headset), or rather when I quit steam, I get the following
dmesg:

[ 7211.963003] xhci_hcd 0000:04:00.0: xHCI host not responding to stop endpoint command.
[ 7211.963019] xhci_hcd 0000:04:00.0: xHCI host controller not responding, assume dead
[ 7211.963037] xhci_hcd 0000:04:00.0: HC died; cleaning up
[ 7211.963053] usb 10-1: USB disconnect, device number 9
[ 7211.963222] usb 11-2: USB disconnect, device number 7
[ 7212.211386] usb 10-2: USB disconnect, device number 10
[ 7212.211390] usb 10-2.3: USB disconnect, device number 11
[ 7212.211392] usb 10-2.3.1: USB disconnect, device number 12
[ 7212.212041] usb 10-2.3.2: USB disconnect, device number 14
[ 7212.212529] usb 10-2.3.3: USB disconnect, device number 15
[ 7212.213010] usb 10-2.3.5: USB disconnect, device number 13

which were the connected USB 3 devices.

After that those USB plugs are dead. I have no figured out how
or even if it is possible to revive them without a reboot.