Freeze if Thunderbolt 3 dock is unplugged while suspended

As discussed here: https://answers.launchpad.net/ubuntu/+question/704136#5 the workaround is to avoid the crash by unloading the crashing driver upon suspend and then reload it on resume.

Install this script (from here) and the issue is resolved:

#!/bin/bash

# Original script was using /bin/sh but shellcheck reporting warnings.

# NAME: custom-xhci_hcd
# PATH: /lib/systemd/system-sleep
# CALL: Called from SystemD automatically
# DESC: Suspend broken for USB3.0 as of Oct 25/2018 various kernels all at once

# DATE: Oct 28 2018.

# NOTE: From comment #61 at: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/522998

TMPLIST=/tmp/xhci-dev-list

# Original script was: case "${1}" in hibernate|suspend)

case $1/$2 in
  pre/*)
    echo "$0: custom-xhci_hcd - going to $2..."
    echo -n '' > $TMPLIST
          for i in `ls /sys/bus/pci/drivers/xhci_hcd/ | egrep '[0-9a-z]+\:[0-9a-z]+\:.*$'`; do
              # Unbind xhci_hcd for first device XXXX:XX:XX.X:
               echo -n "$i" | tee /sys/bus/pci/drivers/xhci_hcd/unbind
           echo "$i" >> $TMPLIST
          done
        ;;
  post/*)
    echo "$0: custom-xhci_hcd - waking up from $2..."
    for i in `cat $TMPLIST`; do
              # Bind xhci_hcd for first device XXXX:XX:XX.X:
              echo -n "$i" | tee /sys/bus/pci/drivers/xhci_hcd/bind
    done
    rm $TMPLIST
        ;;
esac
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