July 28, 2011

Simulate unplug usb device on Linux (USB Reset)


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



and needs mounted usbfs filesystem

 sudo mount -t usbfs none /proc/bus/usb

There is a way to suspend a USB device.  In order to use it, 
you must have a kernel with CONFIG_PM_SYSFS_DEPRECATED turned on.  To 
suspend a device, do (as root):

 echo -n 2 >/sys/bus/usb/devices/.../power/state

where the "..." is the ID for your device.  To unsuspend, do the same 
thing but with a "0" instead of the "2" above.

Note that this mechanism is slated to be removed from the kernel within 
the next year.  Hopefully some other mechanism will take its place.

> To reset a
> device?

Here's a program to do it.  You invoke it as either

 usbreset /proc/bus/usb/BBB/DDD
 usbreset /dev/usbB.D

depending on how your system is set up, where BBB and DDD are the bus and
device address numbers.

Alan Stern


#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");

 return 0;


  1. Hi, great post.

    It's possible simulate these unplug 'x' seconds?
    I need that between unplug and plug exists 15 seconds.

    Thanks very much Tiebing

  2. For those interested in following the hardware route, I implement a trivial and super cheap hardware mechanism for automatically unplugging and replugging my flaky Bluetooth dongle.

    See http://fanjita.org/serendipity/archives/36-Automatic-USB-disconnector.html for info.