When I plug in my no-name USB 2.0 hub with a mouse and a keyboard connected to it, that USB port on my computer stops working: Devices connected to it, whether through a hub or directly, are not detected anymore.
A restart of the system makes the port work again, but I'd rather have a more gentle method, which only "resets" the USB controllers.
I wrote a script that works for me (on Debian 11):
#!/usr/bin/env bash
# Resets all USB host controllers of the system.
# This is useful in case one stopped working
# due to a faulty device having been connected to it.
base="/sys/bus/pci/drivers"
sleep_secs="1"
# This might find a sub-set of these:
# * 'ohci_hcd' - USB 3.0
# * 'ehci-pci' - USB 2.0
# * 'xhci_hcd' - USB 3.0
echo "Looking for USB standards ..."
for usb_std in "$base/"?hci[-_]?c*
do
echo "* USB standard '$usb_std' ..."
for dev_path in "$usb_std/"*:*
do
dev="$(basename "$dev_path")"
echo " - Resetting device '$dev' ..."
printf '%s' "$dev" | sudo tee "$usb_std/unbind" > /dev/null
sleep "$sleep_secs"
printf '%s' "$dev" | sudo tee "$usb_std/bind" > /dev/null
echo " done."
done
echo " done."
done
echo "done."
NOTE:
Idea taken from: https://www.linux.org/threads/resetting-the-usb-subsystem.10404/
usbreset utility in usbutils that does a ioctl(fd, USBDEVFS_RESET, 0) on /dev/bus/usb/$bus/$dev. Don't know how effective it would be in your use case.
Commented
Jun 1, 2022 at 13:29
usbreset (from usbutils) only works with devices, not controllers (root hubs). When I run usbutils with no options, I get a list of (attached) devices but no controllers or root hubs. If I run [sudo] usbreset against a controller/root hub (dev set to 001), usbreset prints No such device found and exits.
if statement around the reset code: my system has /sys/bus/pci/drivers/ehci-pci, but no controllers in that directory.