257

Is it possible to reset the connection of a USB device, without physically disconnecting/connecting from the PC?

Specifically, my device is a digital camera. I'm using gphoto2, but lately I get "device read errors", so I'd like to try to do a software-reset of the connection.

From what I can tell, there are no kernel modules being loaded for the camera. The only one that looks related is usbhid.

3
  • Which version of Ubuntu are you using?
    – User
    Aug 1, 2010 at 20:15
  • i tried both solutions by Li Lo and ssokolow, all i get is permission denied, nomatter if i use the usbreset code or the command line "echo 0 > ..." i use sudo, also my usb devices are owned by root but i can use them without admin rights(cameras..)
    – user290672
    Jun 8, 2014 at 16:40
  • 1
    If you are getting read errors, you might have some data corruption. If your camera uses an external memory card (such as MicroSD), it might be wise to connect it to the computer and run fsck. Jun 8, 2014 at 18:47

20 Answers 20

174

Save the following as usbreset.c

/* usbreset -- send a USB port reset to a USB device */

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ioctl.h>

#include <linux/usbdevice_fs.h>


int main(int argc, char **argv)
{
    const char *filename;
    int fd;
    int rc;

    if (argc != 2) {
        fprintf(stderr, "Usage: usbreset device-filename\n");
        return 1;
    }
    filename = argv[1];

    fd = open(filename, O_WRONLY);
    if (fd < 0) {
        perror("Error opening output file");
        return 1;
    }

    printf("Resetting USB device %s\n", filename);
    rc = ioctl(fd, USBDEVFS_RESET, 0);
    if (rc < 0) {
        perror("Error in ioctl");
        return 1;
    }
    printf("Reset successful\n");

    close(fd);
    return 0;
}

The run the following commands in terminal:

  1. Compile the program:

    $ cc usbreset.c -o usbreset
    
  2. Get the Bus and Device ID of the USB device you want to reset:

    $ lsusb  
    Bus 002 Device 003: ID 0fe9:9010 DVICO  
    
  3. Make our compiled program executable:

    $ chmod +x usbreset
    
  4. Execute the program with sudo privilege; make necessary substitution for <Bus> and <Device> ids as found by running the lsusb command:

    $ sudo ./usbreset /dev/bus/usb/002/003  
    

Source of above program: http://marc.info/?l=linux-usb&m=121459435621262&w=2

12
  • 3
    This works with ubuntu 13.10. The device ID can vary. TO get it for the mouse I have wrapped above code in few shell commands echo $(lsusb | grep Mouse) mouse=$( lsusb | grep Mouse | perl -nE "/\D+(\d+)\D+(\d+).+/; print qq(\$1/\$2)") sudo /path/to/c-program/usbreset /dev/bus/usb/$mouse
    – knb
    Dec 22, 2013 at 11:04
  • 1
    my external drive seems to become undetectable (I have to hard reconnect the usb cable); it is a usb2.0 connected on a usb3.0 desktop PC port; when I run usbreset /dev/bus/usb/011/001 that is one of the 2 usb 3.0 root hubs at lsusb, it errors: "Error in ioctl: Is a directory", any ideia? I tried on both usb 3.0 hubs Oct 30, 2014 at 3:34
  • 1
    If anyone reading this have a (usb) mouse freeze after logging in on Ubuntu 16.04 (with dmesg filled by "input irq status -75") , i can confirm that this is the only solution that worked for me. Thank you May 2, 2016 at 12:31
  • 2
    @ Aquarius, I also get the same error "Error in ioctl: Is a directory". Is it resolved ?
    – ransh
    Feb 12, 2017 at 13:21
  • 17
    At least in Debian 10 and Ubuntu 20.04 there is no need to self-compile - /usr/bin/usbreset is part of the package usbutils. Note that this one uses device ID's instead Bus/Dev-number - simply call 'usbreset 0fe9:9010' in the above case.
    – spawn
    Nov 26, 2020 at 21:35
99

I haven't found myself in your specific circumstances before, so I'm not sure if it'll do enough, but the simplest way I've found to reset a USB device is this command: (No external apps necessary)

sudo sh -c "echo 0 > /sys/bus/usb/devices/1-4.6/authorized"
sudo sh -c "echo 1 > /sys/bus/usb/devices/1-4.6/authorized"

That's the actual one I use to reset my Kinect since libfreenect seems to have no API for putting it back to sleep. It's on my Gentoo box, but the kernel should be new enough to use the same path structure for sysfs.

Yours obviously wouldn't be 1-4.6 but you can either pull that device path from your kernel log (dmesg) or you can use something like lsusb to get the vendor and product IDs and then use a quick command like this to list how the paths relate to different vendor/product ID pairs:

for X in /sys/bus/usb/devices/*; do 
    echo "$X"
    cat "$X/idVendor" 2>/dev/null 
    cat "$X/idProduct" 2>/dev/null
    echo
done
16
  • 16
    Thank you worked great! Maybe you should also mention to perform a echo 1 > /sys/bus/usb/devices/whatever/authorized inside a script to re-enable the device as soon as it has been disabled. I did it on both my mouse and usb keyboard and I ended up with a completely deaf system :)
    – Avio
    Apr 28, 2013 at 8:43
  • 1
    It's extremely strange if it automatically re-set the value to 1 as setting it to 0 is telling the system you don't want the device to be "authorized" and therefore inaccessible. Oct 18, 2013 at 19:45
  • 6
    A note for anyone who tries to switch to the | sudo tee ... approach to privileged /sys writes: That breaks badly if you don't already have your sudo credentials cached. sudo sh -c "..." works as expected when sudo needs to prompt for a password.
    – ssokolow
    Jun 5, 2016 at 10:40
  • 5
    find /sys/bus/usb/devices/*/authorized -exec sh -c 'echo 0 > ${0}; echo 1 > ${0}' {} \; worked like charm for me. ty for pointing at the authorized files.
    – Marc Bredt
    Mar 5, 2018 at 10:46
  • 2
    @MarcH no this certainly doesn't power-cycle a USB device. Even the USBDEVFS_RESET ioctl() does not have that power. I have yet to see some hardware (a motherboard) that supports power-cycling a USB port. But moreover, this /sys/bus/usb/devices/*/authorized thing does not even seem to bring the port into the "reset requested" state (data+/- both low for a fraction of a second). But, it does make my custom CDC ACM device show all signs of an actual reset... is this possibly a mere reload of the SW stack, on the host PC and on the slave, for the USB port indicated?
    – frr
    Mar 3, 2022 at 21:57
86

This will reset all of USB1/2/3 attached ports[1]:

for i in /sys/bus/pci/drivers/[uoex]hci_hcd/*:*; do
  [ -e "$i" ] || continue
  echo "${i##*/}" > "${i%/*}/unbind"
  echo "${i##*/}" > "${i%/*}/bind"
done

I believe this will solve your problem. If you do not want to reset all of the USB endpoints, you can use appropriate device ID from /sys/bus/pci/drivers/ehci_hcd


Notes: [1]: the *hci_hcd kernel drivers typically control the USB ports. ohci_hcd and uhci_hcd are for USB1.1 ports, ehci_hcd is for USB2 ports and xhci_hcd is for USB3 ports. (see https://en.wikipedia.org/wiki/Host_controller_interface_(USB,_Firewire))

15
  • do you believe it may work to wakeup an usb storage? Jun 30, 2014 at 5:53
  • 2
    Although I've received the following message: ls: cannot access /sys/bus/pci/drivers/ehci_hcd/: No such file or directory this has resolved the issue, the mouse has started working immediately. +1 Oct 10, 2014 at 6:16
  • 2
    @Otheus OHCI and UHCI are the USB 1.1 host standards, EHCI is the USB 2.0 host standard, and XHCI is the USB 3.0 host standard.
    – ssokolow
    Jul 20, 2016 at 19:02
  • 6
    This is a beautiful solution. However, on some later Kernels and other *nix distributions, you will find that you need to substitute *hci_hcd with *hci-pci, as the hci_hcd driver is already compiled into the Kernel.
    – not2qubit
    Mar 1, 2017 at 17:14
  • 2
    On a Banana Pi, there apparently is no PCI bus, I had to use the following: for i in /sys/bus/usb/drivers/*/*:*; do Jun 29, 2017 at 9:14
31

Since the APT package usbutils provides the usbreset binary you can just reset the USB device by:

usbreset ${USB_ID}

e.g.
usbreset 0d8c:0102
5
  • very simple solution! Jan 24, 2022 at 16:21
  • To find the device's id you can use lsusb
    – GammaGames
    Mar 30, 2022 at 16:25
  • Or you can just run usbreset without arguments and it will list all the USB devices.
    – snap
    Jul 26, 2022 at 18:26
  • 2
    This should be the accepted answer rather than compiling my own tools! Sep 26, 2023 at 11:56
  • Yes, indeed. when running the usbreset it give you the 3 options to pass the desired device to reset. So you can even just use the device name like this: sudo usbreset "USB Laser Mouse"
    – Barry
    Nov 18, 2023 at 20:02
21

I've created a Python script that simplifies the whole process based on answers here.

Save the script below as reset_usb.py or clone this repo.

Usage:

python reset_usb.py help  # Show this help
sudo python reset_usb.py list  # List all USB devices
sudo python reset_usb.py path /dev/bus/usb/XXX/YYY  # Reset USB device using path /dev/bus/usb/XXX/YYY
sudo python reset_usb.py search "search terms"  # Search for USB device using the search terms within the search string returned by list and reset matching device
sudo python reset_usb.py listpci  # List all PCI USB devices
sudo python reset_usb.py pathpci /sys/bus/pci/drivers/.../XXXX:XX:XX.X  # Reset PCI USB device using path /sys/bus/pci/drivers/.../XXXX:XX:XX.X
sudo python reset_usb.py searchpci "search terms"  # Search for PCI USB device using the search terms within the search string returned by listpci and reset matching device

Script:

#!/usr/bin/env python
import os
import sys
from subprocess import Popen, PIPE
import fcntl

instructions = '''
Usage: python reset_usb.py help : Show this help
       sudo python reset_usb.py list : List all USB devices
       sudo python reset_usb.py path /dev/bus/usb/XXX/YYY : Reset USB device using path /dev/bus/usb/XXX/YYY
       sudo python reset_usb.py search "search terms" : Search for USB device using the search terms within the search string returned by list and reset matching device
       sudo python reset_usb.py listpci : List all PCI USB devices
       sudo python reset_usb.py pathpci /sys/bus/pci/drivers/.../XXXX:XX:XX.X : Reset PCI USB device using path
       sudo python reset_usb.py searchpci "search terms" : Search for PCI USB device using the search terms within the search string returned by listpci and reset matching device       
       '''


if len(sys.argv) < 2:
    print(instructions)
    sys.exit(0)

option = sys.argv[1].lower()
if 'help' in option:
    print(instructions)
    sys.exit(0)


def create_pci_list():
    pci_usb_list = list()
    try:
        lspci_out = Popen('lspci -Dvmm', shell=True, bufsize=64, stdin=PIPE, stdout=PIPE, close_fds=True).stdout.read().strip().decode('utf-8')
        pci_devices = lspci_out.split('%s%s' % (os.linesep, os.linesep))
        for pci_device in pci_devices:
            device_dict = dict()
            categories = pci_device.split(os.linesep)
            for category in categories:
                key, value = category.split('\t')
                device_dict[key[:-1]] = value.strip()
            if 'USB' not in device_dict['Class']:
                continue
            for root, dirs, files in os.walk('/sys/bus/pci/drivers/'):
                slot = device_dict['Slot']
                if slot in dirs:
                    device_dict['path'] = os.path.join(root, slot)
                    break
            pci_usb_list.append(device_dict)
    except Exception as ex:
        print('Failed to list pci devices! Error: %s' % ex)
        sys.exit(-1)
    return pci_usb_list


def create_usb_list():
    device_list = list()
    try:
        lsusb_out = Popen('lsusb -v', shell=True, bufsize=64, stdin=PIPE, stdout=PIPE, close_fds=True).stdout.read().strip().decode('utf-8')
        usb_devices = lsusb_out.split('%s%s' % (os.linesep, os.linesep))
        for device_categories in usb_devices:
            if not device_categories:
                continue
            categories = device_categories.split(os.linesep)
            device_stuff = categories[0].strip().split()
            bus = device_stuff[1]
            device = device_stuff[3][:-1]
            device_dict = {'bus': bus, 'device': device}
            device_info = ' '.join(device_stuff[6:])
            device_dict['description'] = device_info
            for category in categories:
                if not category:
                    continue
                categoryinfo = category.strip().split()
                if categoryinfo[0] == 'iManufacturer':
                    manufacturer_info = ' '.join(categoryinfo[2:])
                    device_dict['manufacturer'] = manufacturer_info
                if categoryinfo[0] == 'iProduct':
                    device_info = ' '.join(categoryinfo[2:])
                    device_dict['device'] = device_info
            path = '/dev/bus/usb/%s/%s' % (bus, device)
            device_dict['path'] = path

            device_list.append(device_dict)
    except Exception as ex:
        print('Failed to list usb devices! Error: %s' % ex)
        sys.exit(-1)
    return device_list


if 'listpci' in option:
    pci_usb_list = create_pci_list()
    for device in pci_usb_list:
        print('path=%s' % device['path'])
        print('    manufacturer=%s' % device['SVendor'])
        print('    device=%s' % device['SDevice'])
        print('    search string=%s %s' % (device['SVendor'], device['SDevice']))
    sys.exit(0)

if 'list' in option:
    usb_list = create_usb_list()
    for device in usb_list:
        print('path=%s' % device['path'])
        print('    description=%s' % device['description'])
        print('    manufacturer=%s' % device['manufacturer'])
        print('    device=%s' % device['device'])
        print('    search string=%s %s %s' % (device['description'], device['manufacturer'], device['device']))
    sys.exit(0)

if len(sys.argv) < 3:
    print(instructions)
    sys.exit(0)

option2 = sys.argv[2]

print('Resetting device: %s' % option2)


# echo -n "0000:39:00.0" | tee /sys/bus/pci/drivers/xhci_hcd/unbind;echo -n "0000:39:00.0" | tee /sys/bus/pci/drivers/xhci_hcd/bind
def reset_pci_usb_device(dev_path):
    folder, slot = os.path.split(dev_path)
    try:
        fp = open(os.path.join(folder, 'unbind'), 'wt')
        fp.write(slot)
        fp.close()
        fp = open(os.path.join(folder, 'bind'), 'wt')
        fp.write(slot)
        fp.close()
        print('Successfully reset %s' % dev_path)
        sys.exit(0)
    except Exception as ex:
        print('Failed to reset device! Error: %s' % ex)
        sys.exit(-1)


if 'pathpci' in option:
    reset_pci_usb_device(option2)


if 'searchpci' in option:
    pci_usb_list = create_pci_list()
    for device in pci_usb_list:
        text = '%s %s' % (device['SVendor'], device['SDevice'])
        if option2 in text:
            reset_pci_usb_device(device['path'])
    print('Failed to find device!')
    sys.exit(-1)


def reset_usb_device(dev_path):
    USBDEVFS_RESET = 21780
    try:
        f = open(dev_path, 'w', os.O_WRONLY)
        fcntl.ioctl(f, USBDEVFS_RESET, 0)
        print('Successfully reset %s' % dev_path)
        sys.exit(0)
    except Exception as ex:
        print('Failed to reset device! Error: %s' % ex)
        sys.exit(-1)


if 'path' in option:
    reset_usb_device(option2)


if 'search' in option:
    usb_list = create_usb_list()
    for device in usb_list:
        text = '%s %s %s' % (device['description'], device['manufacturer'], device['device'])
        if option2 in text:
            reset_usb_device(device['path'])
    print('Failed to find device!')
    sys.exit(-1)
1
  • 2
    this is the best answer to this question.
    – kapad
    Apr 5, 2019 at 7:47
11

I needed to automate this in a python script, so I adapted LiLo's extremely helpful answer to the following:

#!/usr/bin/env python
import os
import sys
from subprocess import Popen, PIPE
import fcntl
driver = sys.argv[-1]
print "resetting driver:", driver
USBDEVFS_RESET= 21780

try:
    lsusb_out = Popen("lsusb | grep -i %s"%driver, shell=True, bufsize=64, stdin=PIPE, stdout=PIPE, close_fds=True).stdout.read().strip().split()
    bus = lsusb_out[1]
    device = lsusb_out[3][:-1]
    f = open("/dev/bus/usb/%s/%s"%(bus, device), 'w', os.O_WRONLY)
    fcntl.ioctl(f, USBDEVFS_RESET, 0)
except Exception, msg:
    print "failed to reset device:", msg

In my case it was the cp210x driver (which I could tell from lsmod | grep usbserial), so you could save the above snippet as reset_usb.py and then do this:

sudo python reset_usb.py cp210x

This might also be helpful if you don't already have a c compiler setup on your system, but you do have python.

5
  • worked for me on a Raspberry
    – webo80
    Jun 23, 2016 at 14:36
  • 1
    A few more words on your solution please. For example, something about the constant USBDEVFS_RESET. Is it always the same for all systems?
    – not2qubit
    Feb 28, 2017 at 7:25
  • @not2qubit USBDEVFS_RESET is the same for all systems. For MIPS it is 536892692.
    – yegorich
    Apr 21, 2017 at 9:09
  • 1
    Newer versions of lsusb seem to need the -t argument (tree mode) to show the driver info that this script is expecting, but the script then needs some updates to parse the different output lines this generates
    – Cheetah
    Oct 19, 2017 at 18:56
  • See my answer here askubuntu.com/a/988297/558070 for a much improved version of this script.
    – mcarans
    Dec 21, 2017 at 10:30
8

Quickest way to reset will be to reset the USB controller itself. Doing so will enforce udev to unregister the device on disconnection, and register is back once you enable it.

echo -n "0000:00:1a.0" | tee /sys/bus/pci/drivers/ehci_hcd/unbind
echo -n "0000:00:1d.0" | tee /sys/bus/pci/drivers/ehci_hcd/unbind
echo -n "0000:00:1a.0" | tee /sys/bus/pci/drivers/ehci_hcd/bind
echo -n "0000:00:1d.0" | tee /sys/bus/pci/drivers/ehci_hcd/bind

This should work for most PC environment. However, if you are using some custom hardware you can simply iterate through the device names. With this method you don't need to find out the device name by lsusb. You can incorporate in a automated script as well.

1
  • 1
    You need to run these commands as root/sudo, and it will not work on all systems (on some, you'll need to replace ehci_hcd with ehci-pci. More info on this solution (perhaps where it came from?): davidjb.com/blog/2012/06/…
    – Lambart
    Nov 5, 2015 at 17:43
6

I'm using kind of sledgehammer by reloading the modules. This is my usb_reset.sh script:

#!/bin/bash

# USB drivers
rmmod xhci_pci
rmmod ehci_pci

# uncomment if you have firewire
#rmmod ohci_pci

modprobe xhci_pci
modprobe ehci_pci

# uncomment if you have firewire
#modprobe ohci_pci

And this is my systemd service file /usr/lib/systemd/system/usbreset.service which runs usb_reset.sh after my diplay manager has started:

[Unit]
Description=usbreset Service
After=gdm.service
Wants=gdm.service

[Service]
Type=oneshot
ExecStart=/path/to/usb_reset.sh
2
  • Using the listpci option of my script here: askubuntu.com/a/988297/558070 will help identify which USB module to reload (eg. xhci_pci, ehci_pci).
    – mcarans
    Jan 24, 2018 at 15:14
  • 7
    Unfortunately on my system these kernel modules are not separate form the kernel, so this won't work: rmmod: ERROR: Module xhci_pci is builtin.
    – unfa
    Jun 28, 2018 at 13:00
6

As the special case of the question is a communication problem of gphoto2 with a camera on USB, there is an option in gphoto2 to reset its USB connection:

gphoto2 --reset

Maybe this option didn't exist in 2010 when the question was asked.

5

I made a python script which will reset a particular USB device based on the device number. You can find out the device number from command lsusb.

for example:

$ lsusb

Bus 002 Device 004: ID 046d:c312 Logitech, Inc. DeLuxe 250 Keyboard

In this string 004 is the device number

import os
import argparse
import subprocess

path='/sys/bus/usb/devices/'

def runbash(cmd):
    p = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE)
    out = p.stdout.read().strip()
    return out

def reset_device(dev_num):
    sub_dirs = []
    for root, dirs, files in os.walk(path):
            for name in dirs:
                    sub_dirs.append(os.path.join(root, name))

    dev_found = 0
    for sub_dir in sub_dirs:
            if True == os.path.isfile(sub_dir+'/devnum'):
                    fd = open(sub_dir+'/devnum','r')
                    line = fd.readline()
                    if int(dev_num) == int(line):
                            print ('Your device is at: '+sub_dir)
                            dev_found = 1
                            break

                    fd.close()

    if dev_found == 1:
            reset_file = sub_dir+'/authorized'
            runbash('echo 0 > '+reset_file) 
            runbash('echo 1 > '+reset_file) 
            print ('Device reset successful')

    else:
            print ("No such device")

def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('-d', '--devnum', dest='devnum')
    args = parser.parse_args()

    if args.devnum is None:
            print('Usage:usb_reset.py -d <device_number> \nThe device    number can be obtained from lsusb command result')
            return

    reset_device(args.devnum)

if __name__=='__main__':
    main()
1
5

Here is script that will only reset a matching product/vendor ID.

#!/bin/bash

set -euo pipefail
IFS=$'\n\t'

VENDOR="045e"
PRODUCT="0719"

for DIR in $(find /sys/bus/usb/devices/ -maxdepth 1 -type l); do
  if [[ -f $DIR/idVendor && -f $DIR/idProduct &&
        $(cat $DIR/idVendor) == $VENDOR && $(cat $DIR/idProduct) == $PRODUCT ]]; then
    echo 0 > $DIR/authorized
    sleep 0.5
    echo 1 > $DIR/authorized
  fi
done
2
  • 1
    I found your script is useful. But what should I do if the $DIR disappears and device is not visible? Oct 13, 2017 at 7:36
  • Did not work in my case. The solution of Tamas worked for me. Sep 27, 2022 at 9:50
1

Try this, it's a software unplug (Eject).

Sometimes doesn't work simply unbind device for some devices.

Example:

I want to remove or eject my "Genius NetScroll 120".

Then i first Check my attached usb device

$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 003: ID 03f0:231d Hewlett-Packard 
Bus 001 Device 004: ID 138a:0007 Validity Sensors, Inc. VFS451 Fingerprint Reader
Bus 001 Device 005: ID 04f2:b163 Chicony Electronics Co., Ltd 
Bus 002 Device 009: ID 0458:003a KYE Systems Corp. (Mouse Systems) NetScroll+ Mini Traveler / Genius NetScroll 120  **<----This my Mouse! XDDD**

Ok, i found my mouse, it's has a Bus 002, Device 009, idVendor 0458 and idProduct 003a, so this is a reference device info about the mouse.

This is important, the Bus number is the begin name path to device and i will check the product Id and Vendor to ensure the correct device to remove.

$ ls /sys/bus/usb/drivers/usb/
1-1/    1-1.1/  1-1.3/  1-1.5/  2-1/    2-1.3/  bind    uevent  unbind  usb1/   usb2/

Pay atention on the folders, check the begining with folder number 2, i will check this one because my Bus is 002, and one by one i have check each folder containing the correct idVendor and idProduct about my mouse info.

In this case, i will retrieve the info with this command:

cat /sys/bus/usb/drivers/usb/2-1.3/idVendor
0458
cat /sys/bus/usb/drivers/usb/2-1.3/idProduct
003a

Ok, the path /sys/bus/usb/drivers/usb/2-1.3/ match with my info mouse! XDDD.

It's time to remove the device!

su -c "echo 1 > /sys/bus/usb/drivers/usb/2-1.3/remove"

Plug again the usb device and it's work again!

1
  • 10
    What if you can't plug it in again? (for example it's an internal sdcard reader)
    – aleb
    Jun 29, 2014 at 20:57
1

Did somebody order a sledgehammer? This is pieced together from various other answers here.

#!/bin/bash

# Root required
if (( UID )); then
        exec sudo "$0" "$@"
fi

cd /sys/bus/pci/drivers

function reinit {(
        local d="$1"
        test -e "$d" || return

        rmmod "$d"

        cd "$d"

        for i in $(ls | grep :); do
                echo "$i" > unbind
        done

        sleep 1

        for i in $(ls | grep :); do
                echo "$i" > bind
        done

        modprobe "$d"

)}

for d in ?hci_???; do
        echo " - $d"
        reinit "$d"
done
7
  • Mark, have you found that the unbinding is really necessary or is it here just to be on the safe side?
    – ndemou
    Nov 10, 2016 at 14:27
  • 1
    This is a sledgehammer, it probably does a lot of unnecessary things Nov 10, 2016 at 14:37
  • @MarkKCowan , How do you use it? What are the command arguments needed/expected?
    – not2qubit
    Feb 28, 2017 at 7:15
  • 1
    @not2qubit: No command-line arguments required. The $@ in the sudo proxy is just a force of habbit, having it prevents bugs if I later decide to add arguments (and forget to update the sudo proxy). Nov 21, 2017 at 14:54
  • 1
    @MarkKCowan Doh! Sorry mate! Oh yes of curse! I should not be commenting on this site while sleepy. Upvoted!
    – not2qubit
    Nov 21, 2017 at 16:29
1

Sometimes I want to perform this operation on a particular device, as identified by VID (vendor id) and PID (product id). This is a script I've found useful for this purpose, that uses the nifty libusb library.

First run:

sudo apt-get install libusb-dev

Then, this c++ file's resetDeviceConnection should perform this task, of resetting a device connection as identified by vid and pid.

#include <libusb-1.0/libusb.h>

int resetDeviceConnection(UINT_16 vid, UINT_16 pid){
    /*Open libusb*/
    int resetStatus = 0;
    libusb_context * context;
    libusb_init(&context);

    libusb_device_handle * dev_handle = libusb_open_device_with_vid_pid(context,vid,pid);
    if (dev_handle == NULL){
      printf("usb resetting unsuccessful! No matching device found, or error encountered!\n");
      resetStatus = 1;
    }
    else{
      /*reset the device, if one was found*/
      resetStatus = libusb_reset_device(dev_handle);
    }
    /*exit libusb*/
    libusb_exit(context);
    return resetStatus;
}

(stolen from my personal TIL catalog: https://github.com/Marviel/TIL/blob/master/unix_tools/Reset_specific_USB_Device.md)

4
  • 3
    Please can you show how this script is run. Dec 29, 2016 at 14:28
  • Sure thing, let me update.
    – Marviel
    Dec 29, 2016 at 20:31
  • 1
    @Marviel, we're still waiting for an update...
    – not2qubit
    Feb 28, 2017 at 7:18
  • needs downvote as useless Oct 13, 2017 at 7:36
1

i made a simple bash script for reset particular USB device.

#!/bin/bash
#type lsusb to find "vendor" and "product" ID in terminal
set -euo pipefail
IFS=$'\n\t'

#edit the below two lines of vendor and product values using lsusb result
dev=$(lsusb -t | grep usbdevicename | grep 'If 1' | cut -d' ' -f13|cut -d"," -f1)
#VENDOR=05a3
#PRODUCT=9230
VENDOR=$(lsusb -s $dev | cut -d' ' -f6 | cut -d: -f1)
PRODUCT=$(lsusb -s $dev | cut -d' ' -f6 | cut -d: -f2)

for DIR in $(find /sys/bus/usb/devices/ -maxdepth 1 -type l); do
  if [[ -f $DIR/idVendor && -f $DIR/idProduct &&
        $(cat $DIR/idVendor) == $VENDOR && $(cat $DIR/idProduct) == $PRODUCT ]]; then
    echo 0 > $DIR/authorized
    sleep 0.5
    echo 1 > $DIR/authorized
  fi
done
0

If you know your device name, this python script will work:

#!/usr/bin/python
"""
USB Reset

Call as "usbreset.py <device_file_path>"

With device_file_path like "/dev/bus/usb/bus_number/device_number"
"""
import fcntl, sys, os

USBDEVFS_RESET = ord('U') << (4*2) | 20

def main():
    fd = os.open(sys.argv[1], os.O_WRONLY)
    if fd < 0: sys.exit(1)
    fcntl.ioctl(fd, USBDEVFS_RESET, 0)
    os.close(fd)
    sys.exit(0)
# end main

if __name__ == '__main__':
    main()
0

This is a very elegant and yet ugly way of doing it. I ran a shell line in cpp which uses python to reset the usb.

  1. install the python usb library: sudo pip3 install pyusb

  2. get the ID of the vendor and product so you can use it in the code: lsusb -v

  3. copy-paste the follwing code but remember to replace <vendor_id> and <product_id> with the vendor ID and product ID that you found in the previous step:

#include <iostream>

int main()
{
    int res = system("echo \"from usb.core import find as finddev; dev=finddev(idVendor=<vendor_id>,idProduct=<product_id>); dev.reset()\" | python3");

    return res;
}
1
  • 1
    Why do you wrap Python code with C++? Very ugly and serves no purpose. Downvoted.
    – snap
    Jul 26, 2022 at 18:28
0

Pure bash script for finding which USB device and driver provide a given network interface, and then resetting the device by unbinding and rebinding that driver:

#!/usr/bin/env bash
DEV=${1-eth1}

DRIVER=$(readlink -f /sys/class/net/$DEV/device/driver) # E.g. /sys/bus/usb/drivers/ax88179_178a
DEVICE=$(find $DRIVER -name '*:*' -printf %f) # E.g. 4-2:1.0

echo $DEVICE > $DRIVER/unbind
echo $DEVICE > $DRIVER/bind
0

So far I came to the conclusion that you cannot control the power of a USB port. The 5V USB is always provided, and it's up to the device to use it or not. You can check this with a 5V fan or light.

So there's no perfect way to make a USB reset. Nevertheless,

I've tried various methods found on stackoverflow, stackexchange etc, (disconnect/reconnect/bind/unbind/reset signal). Best so far are bind/unbind as it forces a cold restart of the device (but no power cycle).

I came up with a solution to reset USB devices, ports and controllers in a python script, which supports all of the above methods. You can find the script at my Github page

Install with pip install usb_resetter

Usage:

usb_resetter --help

#Example:
usb_resetter -d 8086:1001 --reset-hub

The script uses among others the following solution to reset USB hubs/controllers:

Unbindind a USB port / controller works best via:

echo "myhub" > "/sys/bus/usb/drivers/usb/unbind"
echo "myhub" > "/sys/bus/usb/drivers/usb/bind"

Where myhub is found in /sys/bus/usb/devices/*

Or litteral controllers:

echo "mycontroller" > "/sys/bus/pci/drivers/unbind"
echo "mycontroller" > "/sys/bus/pci/drivers/bind"

Where mycontroller is found in /sys/bus/pci/drivers/[uoex]hci_hcd/*:*

-1

Perhaps this works for a camera, too:

Following revived a starved USB 3.0 HDD on a 3.4.42 (kernel.org) Linux on my side. dmesg told, that it was timing out commands after 360s (sorry, I cannot copy the syslog here, not connected networks) and the drive hung completely. Processes accessing the device were blocked in the kernel, unkillable. NFS hung, ZFS hung, dd hung.

After doing this, everything worked again. dmesg told just a single line about the USB device found.

I really have no idea what following does in detail. But it worked.

The following example output is from Debian Squeeze with 2.6.32-5-686 kernel, so I think it works for 2.6 and above:

$ ls -al /dev/sdb
brw-rw---T 1 root floppy 8, 16 Jun  3 20:24 /dev/sdb

$ ls -al /sys/dev/block/8:16/device/rescan
--w------- 1 root root 4096 Jun  6 01:46 /sys/dev/block/8:16/device/rescan

$ echo 1 > /sys/dev/block/8:16/device/rescan

If this does not work, perhaps somebody else can figure out how to send a real reset to a device.

1
  • To the downvoter: Why? If you are unhappy with some wording, you can always suggest an edit. Also: Please check, which answers were here at the time this was posted. Please do not compare with the versions of the others as seen today, compare with the versions of the others as seen back then! Thank you very much.
    – Tino
    Feb 2, 2020 at 16:30

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .