Change FTDI USB-Serial latency in Linux

If you try to change the settings like this, it won't work:

  # cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
    1
  # echo 16 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
  # cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
    1

The low_latency flag is set by default, which forces it to 1, always. You have to run the follwing command to disable it:

  # setserial /dev/ttyUSB0 ^low_latency

Then you can modify the latency_timer entry:

  # cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
    16
  # echo 8 > /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
  # cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer
    8