Archived post from my old blog (2007–2016), restored from the Wayback Machine. It is published as written at the time; tools and versions are likely out of date.

On Ubuntu sometimes wakeup from suspend “forgets” to wake up some pieces
Last time it happened it was the usb3 system
In order to reactivate it I had to do the following:

lspci | grep USB
...
03:00.0 USB controller: Fresco Logic FL1000G USB 3.0 Host Controller (rev 01)
...
ls -la /sys/bus/pci/drivers/xhci_hcd/
....
lrwxrwxrwx  1 root root    0 mar  1 18:16 0000:03:00.0
...
sudo echo -n "0000:03:00.0" | sudo tee /sys/bus/pci/drivers/xhci_hcd/unbind
sudo echo -n "0000:03:00.0" | sudo tee /sys/bus/pci/drivers/xhci_hcd/bind

notice that I did the unbind of the usb3 (xchi) module on the main usb device

That was it, after this usb3 ports began to work again