3G Modem on Ubuntu 12.04 – Rebind USB on Failure – see http://goo.gl/aMS9B

rebind_qcserial.sh

#!/bin/bash

##  Author: Philipp Klaus <philipp.klaus → AT → gmail.com>
##  See <http://goo.gl/aMS9B> and <http://lwn.net/Articles/143397/>

if [ $(id -u) != 0 ];then
  echo "must be run as root"
  exit 2
fi

usage () {
    echo "\nusage: $0 <serial modem device>\n\nexample: $0 /dev/ttyUSB0\n" >&2; exit 1
}

[ -z "$1" ] && usage

dev=$(basename $1)
sd_path="/sys/bus/usb/drivers/qcserial"
sleep_time=4

for dir in $(ls $sd_path/ | egrep -v "bind|module|new_id|remove_id|uevent|unbind"); do
  if [ -n "$(ls $sd_path/$dir/$dev)" ]; then
    echo "Rebinding $dir on $sd_path"
    echo -n $dir > $sd_path/unbind
    sleep $sleep_time
    echo -n $dir > $sd_path/bind
    sleep $sleep_time
    killall modem-manager
    sleep $sleep_time
    service network-manager restart
  fi
done