> Here is usbserial.c from 2.4.23 that supports reserving
> USB serial ports by the device serial number.
> 
> I have tested it briefly.  It is a small change to
> usbserial.c.  It has a very crude interface.  It should
> be trivial to backport to earlier 2.4 kernels.
> 
> For example, the modprobe command below reserves ttyUSB0
> to ttyUSB3 for an EP/4s with serial numbers A32399053-0
> and A32399053-1 (this device looks like a hub with 2
> separate 2 port devices, each device has its own serial
> number) and ttyUSB4 to ttyUSB11 for an Edgeport/8 with
> serial number V30717011-0. 
> 
> modprobe usbserial reserve_ports=A32399053-0,A32399053-0,A32399053-1,A32399053-1,V30717011-0,V30717011-0,V30717011-0,V30717011-0,V30717011-0,V30717011-0,V30717011-0,V30717011-0
> 
> (The line has been wrapped by my email program.)
> 
> Notice that the serial number must be repeated for each port
> to be reserved.  This could be changed to something like this:
> 
> modprobe usbserial reserve_ports=A32399053-0,2,A32399053-1,2,V30717011-0,8
> 
> where the serial number is followed by the number of ports to
> reserve.  (The line has been wrapped by my email program.)
> 
> There might be a problem in supporting devices with a comma in
> the serial number, I would have to experiment with this.
> 
> Remaining things to do with time estimates:
> 
>   1. Improve the user interface (?)  The change suggested above
>      would take (1/2 day).
>   2. Testing. (1 day)
>   3. Determine installation and configuration process,
>      document for users, and prepare a release.  (1 day)
>   4. Submit to kernel, may require coding changes.  (1 hour to 1 day)
>   5. Port to 2.6 kernel.  (2 days)
> 
> -- Al