USB Device Port Affinity in Linux

Question

I'm running a linux machine (Ubuntu 10.04) inside of an autonomous submarine that has many USB devices attached to it such as cameras, usb->serial devices, etc. Unfortunately, every time the machine boots up my devices seem to get assigned differently. For example, my various USB->serial devices will show up as different /dev/ttyUSB*, and my cameras will show up as different /dev/video*.

Is there some way to force these USB devices to get consistently assigned to the same /dev files?

Answer 1

Write udev rules that give each device a known symlink under /dev.

Answer 2

The devices send a serial number when they connect that is available for udev rules. But there is already a location, at least on my system, where these are symlinked to the actual device nodes. look in /dev/input/by-id for input devices. You can do similar things for USB serial ports if it's not already there.