planetceres / RESET_USB_KERNEL_MODULE.md
Restart USB ports after a power overdraw (error -110). Unplug all devices prior to running script.
for port in $(lspci | grep USB | cut -d' ' -f1); do echo -n "0000:$"| sudo tee /sys/bus/pci/drivers/xhci_hcd/unbind; sleep 5; echo -n "0000:$" | sudo tee /sys/bus/pci/drivers/xhci_hcd/bind; sleep 5; done for port in $(lspci | grep xHCI | cut -d' ' -f1); do echo -n "0000:$"| sudo tee /sys/bus/pci/drivers/xhci_hcd/unbind; sleep 5; echo -n "0000:$" | sudo tee /sys/bus/pci/drivers/xhci_hcd/bind; sleep 5; done Either my Dell Optiplex 990 computer or my Linux install has an issue: occasionally, when I re-plug a USB device into the system, it’ll cause a fault in the USB module in the kernel and USB goes dark. I’m unsure as to whether this is a hardware or software issue, but I’d simply like to restart my USB subsystem and continue working. When searching the web for ‘restart USB in Linux’ and ‘reload USB kernel module’, you get a plethora of results and none of which will work (seemingly due to how the Ubuntu standard kernel is compiled), at least for me within Ubuntu 12.04, Precise Pangolin. Until now, I’ve had no success and had to hard reset. No longer.
You’ll need root/sudo access to the machine to be able to run commands. In my case, without USB available, then I’ve either got to sprint for a PS/2 keyboard and mouse or login via SSH. You can do what I’ve done and prepared things into a suitable script I can run with just a Gnome launcher. Thanks to this fantastic post for the help. Either place the following into a script or run the commands directly:
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 The hardware identifiers being passed around here can be revealed using a command like lspci | grep USB. In my case, the identifiers in the original post were exactly what I have in my system.
I’m yet to see if my USB will correctly come back online after freezing up as it hasn’t happened yet, but I’ll try this when it does and report back. That said, the commands above definitely reload all USB devices attached to the system; that much I’ve tried.
How do I reset an USB device without unplugging it in Linux?
Every now and then there might come a need to reset a USB device, is there a way to perform the reset in software without unplugging the device itself and then pluggin it back in? More specifically I have a webcam which gets confused when playing too much with the settings in guvcapture and then needs a reset to get back on track.
5 Answers 5
usbutils includes usbreset.
Run it without any arguments to see usage and a list of devices. It requires superuser access to actually reset devices.
Usage: usbreset PPPP:VVVV - reset by product and vendor id usbreset BBB/DDD - reset by bus and device number usbreset "Product" - reset by product name This allows resetting individual devices which is an improvement over some answers that reset the entire bus. It might not resolve intermediary hub/bus issues, but it’s a lot less disruptive to only reset the desired device.
You could try Benjamin Close’s resetusb program to reset all devices — there are no binaries available, but compiling it is rather easy. Save the source code as resetusb.c , then run:
gcc -lusb resetusb.c -o resetusb You can now run the tool as resetusb . Alternatively, @unhammer points to Alan Stern’s single-device version (plus some hints on how to use it).
modprobe -vr ehci_hcd modprobe -v ehci_hcd (you could of course script this)
Some distributions may also have their own tools to restart the USB subsystem; Mandrake apparently has /etc/init.d/usb .
$ sudo modprobe -vr ehci_hcd results in modprobe: FATAL: Module ehci_hcd is builtin. on kubuntu trusty.
On my laptop with debian 8, ehci_hcd gives errors. However, rmmod ehci_pci && sleep 2 && modprobe ehci_pci works perfectly.
Let’s say I want to reset /dev/sdc .
# udevadm info -q all /dev/sdc | grep DEVPATH E: DEVPATH=/devices/pci0000:00/0000:00:14.0/usb2/2-1/2-1.4/2-1.4:1.0/host2/target2:0:0/2:0:0:0/block/sdc I take the 2-1.4 above (yours might just be 2-1 — my device is plugged into a hub) and do:
# echo 2-1.4 > /sys/bus/usb/drivers/usb/unbind # echo 2-1.4 > /sys/bus/usb/drivers/usb/bind I’ve made a one-liner(-ish) for that: DEV=»sdc»; USB=$(udevadm info -q all /dev/$DEV | grep DEVPATH | grep -o ‘/usb2*/[1-9,-]*’ | cut -d’/’ -f3); echo $USB > /sys/bus/usb/drivers/usb/unbind; echo $USB > /sys/bus/usb/drivers/usb/bind Make DEV the drive you want to reset, and run — it’ll extract the USB port number and unbind/bind it (untested).
You can restart the hardware abstraction layer: sudo /etc/init.d/hal restart
i think HAL is replaced by something else in the newest version of ubuntu.. so its depend of distrib..
I seriously doubt it would have worked anyway. HAL wasn’t a low-level abstraction layer like the Windows component of the same name.
I’ve created a Python script that simplifies the whole process:
Save the script below as reset_usb.py or clone this repo.
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 #!/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_dictRestart usb system linux] = 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 = 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) Restarting USB subsystem in CentOS
After a long uptime specific (cheap) devices or components connected to the USB ports lock up or malfunction. Unplugging and plugging them usually fixes issues, but physical access to the system (especially a remote server) is neither always possible or desirable.
In cases like this, Linux (unlike Windows) can trigger a USB subsystem restart by deactivating and reactivating the USB controller(s).
The hardware ID(s) of the controllers differ from manufacturer to manufacturer and from hardware to hardware. So the first thing to do is find out the correct hardware ID(s).
cd /sys/bus/pci/drivers/ehci_hcd
ls
returns a list of one or more controller IDs, in the form of 0000:00:xx.y.
Edit: For USB 3.0 controllers, use instead
cd /sys/bus/pci/drivers/xhci_hcd
ls
On my system which has two AMD USB controllers, the following IDs are found:
0000:00:12.2 0000:00:13.2 bind module new_id remove_id uevent unbind
Now that the ID or IDs are known, you need to run a set of commands that trigger the disabling and re-enabling of that device. You can run this command for a specific controller (if you know which one) or for all controllers if you don’t have anything critical connected to the USB. The command is:
Remember to enable them back:
where instead of xx.y you fill in the correct set of numbers to use the IDs discovered above.
This procedure is the same for all RHEL-like distributions (Red Hat Enterprise, CentOS, Fedora).