Re: Multiple device attachments

[Eduardo Horvath <eeh%NetBSD.org@localhost>]

On Thu, 21 Jul 2011, Frank Zerangue wrote:

> The examples you site seem to indicate that for example the le device may 
> attach to many
> alternative devices (e.g. pci, tc, …), but only one attachment is made when 
> autoconf is complete. I may have 
> read the code examples incorrectly -- please pardon me if I did; but what I 
> want to know is --  can a 
> device have multiple attachments (more than one parent device) when autoconf 
> is complete. 

What we have is a device tree.  That means a device instance can only have 
one parent.  Once it has been instantiated, that instance, with its 
associated instance number, cannot appear anywhere else in the device 
tree.

It might be good to extend the device tree to a directed graph at some 
point to support multi-pathed devices on fabrics like SAS, Fibre-channel, 
or PCIe that allow that sort of thing, but that's a different issue.

Eduardo