usbhidaction with non-HID devices

[Warren Block]

On Tue, 9 Sep 2008, Warren Block wrote:

> My Epson scanner has one button.  I'd like to have that button activate a 
> program.  usbhidaction(1) does that for uhid devices.
>
> Of course, the scanner is not a HID, and usbhidaction doesn't like non-HID 
> devices:
>
>  % usbhidaction -v -c usbhid.conf -f uscanner0
>  usbhidaction: hid_get_report_desc() failed: Operation not supported by 
> device
>
> Is there an existing way to do this?

Responding to my own post:

/usr/ports/sysutils/scanbuttond can do this--if you use ugen instead of 
uscanner.  It polls, but the port shows a clever way to set it up so 
devd starts scanbuttond when the scanner is turned on, and kills it when 
the scanner is turned off.

All of this leads me to ask:

Besides a known device name (uscanner), what does uscanner provide that 
ugen does not?

-Warren Block * Rapid City, South Dakota USA