reset-usb

#!/bin/bash

DRIVERS_DIR=/sys/bus/pci/drivers

# George Hawkins Nov 18th, 2014
# I found various scripts that bind and unbind the USB devices to reset the whole USB system.
# All used hardcoded slots and drivers - slots aren't consistent across machines and driver names change with OS releases.
# This script attempts to discover all values.

# This awk script finds all PCI devices with class 'USB controller' that have a slot and a driver.
# All devices should have a slot, but it's possible for them not to have a driver.
# Important: the quotes around EOF prevent dollar expansion in the here document.
read -d '' get_devices << 'EOF'
/^Slot:/ {
    slot = $2
}

/^Class:.*USB controller/ {
    usb = 1
}

/^Driver:/ {
    if (usb && slot) {
        print slot, $2
    }
}

/^$/ {
    slot = ""
    usb = 0
}
EOF
# Note: rather than 0 read will return 1 as it uses this to signal reaching EOF.

function apply {
    action=$1

    shift

    while (( "$#" ))
    do
        slot=$1
        driver=$2
        shift
        shift

        echo -n $slot > $DRIVERS_DIR/$driver/$action
    done
}

devices=$(lspci -vmmkD | awk "$get_devices")

apply unbind $devices
apply bind $devices