How are USB drivers assigned?

[osp at aloha.com]

On Tue, 29 Jun 2010 17:56:39 +0200 Roland Smith <rsmith at xs4all.nl> wrote:
> On Mon, Jun 28, 2010 at 11:03:38PM -1000, Gary Dunn wrote:
> > Is there a file that associates drivers with USB device information?
> > More specifically, how does a USB mouse get assigned to the ums driver?
> > This is for FreeBSD 8.0, if it matters.
> 
> When queried on connection the mouse identifies itself by sending a
descrip> tor
> as a Human Interface Device class peripheral, and specifically a mouse. The
> USB driver then knows to attach the ums device driver.

Thanks for the reply Roland. 

What I am looking for is 

> The USB driver then knows to attach the ums device driver.

how it "knows."

Gary Dunn
Open Slate Project