# $Id: 91-retro-usb-latency.rules 1194 2019-07-20 07:43:21Z mueller $
# SPDX-License-Identifier: GPL-3.0-or-later
# Copyright 2017- by Walter F.J. Mueller <W.F.J.Mueller@gsi.de>
#
# udev rules to set FTDI USB-serial adaptors to low latency mode
#
# copy into /etc/udev/rules.d
#
# Notes:
# - prior to linux 2.6.32 the default was the built in 16 ms device latency
# - from linux 2.6.32 till 4.4 patch 9589541 low latency (1 ms) was the default
# - the patch https://patchwork.kernel.org/patch/9589541/ reverted this
# - the entered the 4.4.52 and higher kernel lines under the changelog heading
#       USB: serial: ftdi_sio: fix extreme low-latency setting
# - this rule ensures that low (1ms) latency is used
#
ACTION=="add", SUBSYSTEM=="tty", DRIVERS=="ftdi_sio", RUN+="/bin/setserial /dev/$kernel low_latency"
#