udev-ftdi-unload-vcp-driver.sh

#!/bin/bash
#
# This file is part of SerialPundit.
# 
# Copyright (C) 2014-2021, Rishi Gupta. All rights reserved.
#
# The SerialPundit is DUAL LICENSED. It is made available under the terms of the GNU Affero 
# General Public License (AGPL) v3.0 for non-commercial use and under the terms of a commercial 
# license for commercial use of this software. 
#
# The SerialPundit is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
# without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#################################################################################################

# Run this script as root user.

# When a FTDI device is connected to system, linux kernel with udev tries to load appropriate VCP driver
# for connected device. For Linux default VCP driver and d2xx are mutually exclusive. So this script
# tries to unload default VCP driver for FTDI devices.

# Note that once the driver has been unloaded then if the device is un-plugged and plugged again into system
# default driver will get loaded again automatically by udev/kernel. So this script must be run each time
# USB-UART device is plugged into system.

# This has a side effect also that now other programs can not use default FTDI VCP driver, this is due to
# how the FTDI has designed their drivers. It is possible to just unbind default driver for a particular
# device using udev rules (see tools-and-utilities/99-sp-extra-udev.rules for unbinding with the help of script).

# It seems like FTDI D2XX uses user space USB drivers and depends upon libusb for its working. If any error
# is encountered like permission denied place the following udev rules in in /etc/udev/rules.d/ for Ubuntu 
# Linux distribution.
# <github repository>/tools-and-utilities/99-sp-ftdi-d2xx.rules

# Run below shell command to know ftdi vcp driver module is loaded or not.
# lsmod | grep ftdi

set -e
modprobe -r ftdi_sio
echo "ftdi_sio vcp driver unloaded !"