> Walk alldevices and search for a null dv_parent.  

No, pseudo-device also have a NULL parent.

> I doubt our device tree will anything like darwin's anyway.

It's the same devices. Darwin has some additionnal per device info (IO
class for instance), but we can have a BSD name to Darwin class name
translator for the devices we need.

-- 
Emmanuel Dreyfus.
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manu@netbsd.org