Update: I found that my adapter was making a poor connection to the usb cable and when I wiggled the connection I could get hotplug to recognize it regularly. Sorry for the wasted brain power reading this. KS

Hi My Kernel is debian 2.6.9.

I've purchased a USB-Serial cable so that I can connect my rowing machine to my laptop computer. Murphy's law came into play and the laptop has no serial port, but the rowing machine outputs it's signal via a serial port. As a solution, I bought the adapter cable.

When I first plugged in the cable to my laptop ( HP zt1150) the system log file indicated that the serial cable was found and attached to device ttyUSB0. I was able to use things as expected by substuting /dev/ttyUSB0 in where I had used /dev/ttyS0 before on my desktop computer. I was working at 1200 bps 8N1 settings.

I unplugged the cable before I removed the module or shut the system down. After that I can't get it to work again. When I plug it in the system log indicates that it found the adapter and loaded the right driver (pl2303), but it doesn't assign any serial device to the driver.

How can I fix this? Is there some parameter on the modprobe command I can use to specify what device to attach to?

Initial /var/log/syslog :
..snip..
Nov 15 20:51:44 box kernel: usb 2-1: new full speed USB device using address 2
Nov 15 20:51:44 box kernel: drivers/usb/serial/usb-serial.c: USB Serial support registered for Generic
Nov 15 20:51:44 box kernel: usbcore: registered new driver usbserial_generic
Nov 15 20:51:44 box kernel: usbcore: registered new driver usbserial
Nov 15 20:51:44 box kernel: drivers/usb/serial/usb-serial.c: USB Serial Driver core v2.0
Nov 15 20:51:44 box kernel: drivers/usb/serial/usb-serial.c: USB Serial support registered for PL-2303
Nov 15 20:51:44 box kernel: pl2303 2-1:1.0: PL-2303 converter detected
Nov 15 20:51:44 box kernel: usb 2-1: PL-2303 converter now attached to ttyUSB0
Nov 15 20:51:44 box kernel: usbcore: registered new driver pl2303
Nov 15 20:51:44 box kernel: drivers/usb/serial/pl2303.c: Prolific PL2303 USB to serial adaptor driver v0.11
..snip..

And after breaking things:
..snip..
Nov 15 21:30:01 box kernel: drivers/usb/serial/usb-serial.c: USB Serial support registered for Generic
Nov 15 21:30:01 box kernel: usbcore: registered new driver usbserial_generic
Nov 15 21:30:01 box kernel: usbcore: registered new driver usbserial
Nov 15 21:30:01 box kernel: drivers/usb/serial/usb-serial.c: USB Serial Driver core v2.0
Nov 15 21:30:01 box kernel: drivers/usb/serial/usb-serial.c: USB Serial support registered for PL-2303
Nov 15 21:30:01 box kernel: usbcore: registered new driver pl2303
Nov 15 21:30:01 box kernel: drivers/usb/serial/pl2303.c: Prolific PL2303 USB to serial adaptor driver v0.11
..snip..

Please Help. Thanks, KS