usb_resetter

small tool to reset USB controllers, hubs or devices

So here we are, with sh*TTY built usb devices, that don't work properly.

I've had numerous problems with USB devices that simply don't work unless you disconnect / reconnect them. While I'd probably like to throw away those devices, sometimes there's no choice than the rejoice of using those devices.

A couple solutions:

1. Buy a robot hand that unplugs / plugs the device :) - Nice solution but costly... But again, very nice...
2. Reset the USB device (works sometimes)
3. Reset the USB hub where the device is plugged in (is generally sufficient)
4. Reset all USB controllers (a bit broad, but works miracles on reluctant devices)
5. Burn the device and promise to buy better hardware (also very nice solution)

I've scripted solutions 2 to 4 in order to achieve what I need into a Python script.

Setup

Grab yourself a copy of usb_resetter via pypi with pip install usb_resetter or download via

curl -o /usr/local/bin/usb_resetter -L https://raw.githubusercontent.com/netinvent/usb_resetter/main/usb_resetter/usb_resetter.py && chmod +x /usr/local/bin/usb_resetter

Usage

List all USB devices

usb_resetter -l

Result

Found device 1d6b:0002 at /dev/bus/usb/001/001 Manufacturer=Linux 5.14.0-70.26.1.el9_0.x86_64 xhci-hcd, Product=xHCI Host Controller
Found device 0665:5161 at /dev/bus/usb/001/002 Manufacturer=INNO TECH, Product=USB to Serial
Found device 1d6b:0003 at /dev/bus/usb/002/001 Manufacturer=Linux 5.14.0-70.26.1.el9_0.x86_64 xhci-hcd, Product=xHCI Host Controller
Found device 1199:9071 at /dev/bus/usb/002/002 Manufacturer=Sierra Wireless, Incorporated, Product=EM7455

Reset a reluctant USB device

usb_resetter -d [vendor_id]:[product_id] --reset-device

Example:

usb_resetter -d 1199:9071 --reset-device

Result:

Resetting usb device /dev/bus/usb/002/002

Reset the USB hub where a device is connected in

usb_resetter -d [vendor_id]:[product_id] --reset-hub

Example:

usb_resetter -d 1199:9071 --reset-hub

Result:

unbind hub /sys/bus/usb/devices/2-4
bind hub /sys/bus/usb/devices/2-4

Reset hubs without vendor / device ids

You can also reset a hub without knowing the device VID:PID. List the hubs and then select the ones to reset

usb_resetter -l
usb_resetter --reset-hub --hub /dev/bus/usb/001/002

Reset the whole USB controller (usually makes reluctant devices work again)

usb_resetter --reset-all

Result

unbind hub /sys/bus/pci/drivers/xhci_hcd/0000:00:14.0
bind hub /sys/bus/pci/drivers/xhci_hcd/0000:00:14.0

Afterwards, all your USB devices should work as if they were just plugged in, since this reset also temporarily cuts power from given USB device, making it reboot.

Usual suspect: Cypress Semiconductor USB to Serial UPS

These cheap USB UPS have always the same kind of unreliable USB to serial interface. Most of them use blazer_usb driver from NUT, and sometimes the driver can't start because it can't communicate with the UPS. Guess why ? No idea.

Unplugging and plugging the USB port usually fixes this, but that's not handy.

A simple USB device reset isn't sufficient for that one.

We'll need to reset the hub it's attached to.

The command for doing so is:

usb_reset.py --reset-hub --device 0665:5161

While I have a couple of machines running NUT, I modified the nut-driver.service file to automatically reset the device before trying to load the driver:

In /etc/systemd/system/nut-driver.service I added line

ExecStartPre=/usr/local/bin/usb_reset.py --reset-hub --device 0665:5161