USB Reset On Wake From Sleep

Despite a few major short-comings of my Lenovo laptop I still really love it. I am currently traveling a lot so the 3K monitor on a small form-factor and rugged SSD make it a good choice. The one thing lacking is good network support. It has no Ethernet port perhaps because it is too thin; which, is not such a big deal; but I've had lots of trouble with the WiFi card. I replaced it a few times and the the hardware ready-state gets reset sometimes, not sure why.

I like to use a wired network connection whenever I can so I got a D-Link DUB-E100 Ethernet Adapter which is a little dongle that plugs into one of my two USB ports and it works fine, except when waking from sleep the device is not usable.

I found a C program on Ask Ubuntu which also contains a Python version by Peter that I embellished and added as a gist.

#!/usr/bin/env python
# usbreset -- send a USB port reset to a USB device
#
# http://askubuntu.com/questions/645#answer-661
#
# $ sudo usbreset.py DUB
# Looking for device: DUB
# Executing command: `lsusb | grep DUB`
# Subprocess:  b'Bus 001 Device 006: ID 2001:1a02 D-Link Corp. DUB-E100 Fast...'
# Found device 001 on bus 006 for "D-Link Corp. DUB-E100 Fast Ethernet Adapt..."
from __future__ import print_function

import os
import re
import sys
import fcntl
import argparse
import subprocess

USBDEVFS_RESET = 21780

def main():
    command_line = argparse.ArgumentParser(description='USB device reset')

    command_line.add_argument(
        'desc', metavar='DESC',
        type=str, nargs='?', default='USB',
        help='Device description')

    options = command_line.parse_args(sys.argv[1:])

    print('Looking for device:', options.desc)

    lsusb_cmd = 'lsusb | grep {}'.format(options.desc)
    print('Executing command: `{}`'.format(lsusb_cmd))

    lsusb_out = subprocess.check_output(lsusb_cmd, shell=True)
    print('Subprocess: ', lsusb_out.strip())

    parts = re.search(r'Bus (?P<bus>\d+) Device (?P<dev>\d+): ID [:\d\w]+ (?P<desc>.*)$', str(lsusb_out))
    bus = parts.group('bus')
    dev = parts.group('dev')
    desc = parts.group('desc').strip()
    print('Found device {} on bus {} for "{}"'.format(bus, dev, desc))

    f = open('/dev/bus/usb/{}/{}'.format(bus, dev), 'w', os.O_WRONLY)
    fcntl.ioctl(f, USBDEVFS_RESET, 0)

if __name__ == '__main__':
    main()

To execute it manually I give it a unique identifier among USB devices, so I could have given the entire D-Link Corp. DUB-E100 Fast Ethernet Adapter(rev.C1) [ASIX AX88772] description; but, DUB should be enough:

usbreset.py DUB

Here’s the full output surrounded by various networking calls:

stav@venix:~$ ip route get 8.8.8.8
    RTNETLINK answers: Network is unreachable

stav@venix:~$ ls /sys/class/net/
    enx78542ee5c627  lo  wlp1s0

stav@venix:~$ sudo ethtool enx78542ee5c627
    Settings for enx78542ee5c627:
    Advertised link modes:  Not reported
    Advertised pause frame use: No
    Advertised auto-negotiation: No
    Speed: 10Mb/s
    Duplex: Half
    Auto-negotiation: off
    Link detected: no

stav@venix:~$ nmcli g
    STATE         CONNECTIVITY
    disconnected  none

stav@venix:~$ sudo ~/bin/usbreset.py DUB
    Looking for device: DUB
    Executing command: `lsusb | grep DUB`
    Subprocess:  Bus 002 Device 003: ID 2001:1a02 D-Link Corp. DUB-E100 Fast Ethernet Adapter(rev.C1) [ASIX AX88772]
    Found device 002 on bus 003 for "D-Link Corp. DUB-E100 Fast Ethernet Adapter(rev.C1) [ASIX AX88772]"

stav@venix:~$ ip route get 8.8.8.8
    8.8.8.8 via 192.168.1.254 dev enx78542ee5c627  src 192.168.1.72

stav@venix:~$ sudo ethtool enx78542ee5c627
    Settings for enx78542ee5c627:
    Advertised link modes:  10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
    Advertised pause frame use: Symmetric
    Advertised auto-negotiation: Yes
    Speed: 100Mb/s
    Duplex: Full
    Auto-negotiation: on
    Link detected: yes

stav@venix:~$ nmcli g
    STATE      CONNECTIVITY
    connected  full

To get it to run on resume from suspend I compiled it into /opt:

stav@venix:~$ python3 -m compileall bin/usbreset.py
    Compiling 'bin/usbreset.py'...

stav@venix:~$ sudo mkdir /opt/stav

stav@venix:~$ sudo mv bin/__pycache__/usbreset.cpython-35.pyc /opt/stav

stav@venix:~$ ls -l /opt/stav/
    total 4
    -rw-rw-r-- 1 stav stav 1380 nov 27 19:54 usbreset.cpython-35.pyc

Then I added a systemd script to call it with the DUB argument.

/lib/systemd/system-sleep/usbreset:

#!/bin/sh
# http://askubuntu.com/questions/226278/run-script-on-wakeup#answer-620328
case $1/$2 in
    post/suspend)
        /usr/bin/python3  /opt/stav/usbreset.cpython-35.pyc  DUB
        ;;
esac

Works well.