USB trackball

I have a Kensington Expert Mouse I'm attempting to put back in active 
service on my Debian Bookworm system:

eben@cerberus:~$ cat /etc/debian_version
12.13

When I connect it, journalctl says this:

Jun 01 14:29:45 cerberus kernel: usb 1-13: new low-speed USB device 
number 9 using xhci_hcd
Jun 01 14:29:45 cerberus kernel: usb 1-13: New USB device found, 
idVendor=047d, idProduct=1020, bcdDevice= 2.01
Jun 01 14:29:45 cerberus kernel: usb 1-13: New USB device strings: 
Mfr=1, Product=2, SerialNumber=0
Jun 01 14:29:45 cerberus kernel: usb 1-13: Product: Kensington Expert Mouse
Jun 01 14:29:45 cerberus kernel: usb 1-13: Manufacturer: Kensington
Jun 01 14:29:45 cerberus kernel: input: Kensington      Kensington 
Expert Mouse as 
/devices/pci0000:00/0000:00:14.0/usb1/1-13/1-13:1.0/0003:047D:1020.0006/input/input27
Jun 01 14:29:45 cerberus kernel: hid-generic 0003:047D:1020.0006: 
input,hidraw3: USB HID v1.10 Mouse [Kensington      Kensington Expert 
Mouse] on usb-0000:00:14.0-13/input0
Jun 01 14:29:45 cerberus mtp-probe[6440]: checking bus 1, device 9: 
"/sys/devices/pci0000:00/0000:00:14.0/usb1/1-13"
Jun 01 14:29:45 cerberus mtp-probe[6440]: bus: 1, device: 9 was not an 
MTP device
Jun 01 14:29:46 cerberus mtp-probe[6451]: checking bus 1, device 9: 
"/sys/devices/pci0000:00/0000:00:14.0/usb1/1-13"
Jun 01 14:29:46 cerberus mtp-probe[6451]: bus: 1, device: 9 was not an 
MTP device
Jun 01 14:29:46 cerberus kernel: usb 1-13: USB disconnect, device number 9
Jun 01 14:29:53 cerberus kernel: usb 1-13: new low-speed USB device 
number 10 using xhci_hcd
Jun 01 14:29:53 cerberus kernel: usb 1-13: New USB device found, 
idVendor=047d, idProduct=1020, bcdDevice= 2.01
Jun 01 14:29:53 cerberus kernel: usb 1-13: New USB device strings: 
Mfr=1, Product=2, SerialNumber=0
Jun 01 14:29:53 cerberus kernel: usb 1-13: Product: Kensington Expert Mouse
Jun 01 14:29:53 cerberus kernel: usb 1-13: Manufacturer: Kensington
Jun 01 14:29:53 cerberus kernel: input: Kensington      Kensington 
Expert Mouse as 
/devices/pci0000:00/0000:00:14.0/usb1/1-13/1-13:1.0/0003:047D:1020.0007/input/input28
Jun 01 14:29:53 cerberus kernel: hid-generic 0003:047D:1020.0007: 
input,hidraw3: USB HID v1.10 Mouse [Kensington      Kensington Expert 
Mouse] on usb-0000:00:14.0-13/input0
Jun 01 14:29:53 cerberus mtp-probe[6529]: checking bus 1, device 10: 
"/sys/devices/pci0000:00/0000:00:14.0/usb1/1-13"
Jun 01 14:29:53 cerberus mtp-probe[6529]: bus: 1, device: 10 was not an 
MTP device
Jun 01 14:29:54 cerberus mtp-probe[6541]: checking bus 1, device 10: 
"/sys/devices/pci0000:00/0000:00:14.0/usb1/1-13"
Jun 01 14:29:54 cerberus mtp-probe[6541]: bus: 1, device: 10 was not an 
MTP device

As with cars, it ran when parked.  Now, the pointer doesn't move when I 
use it, not even a little bit.  xev doesn't recognize any button 
(including the scroll wheel).  Any clues?  Maybe X doesn't know what to 
do with it?