Re: USB gadget support?

[Dan Williams <dcbw redhat com>]

On Tue, 2012-02-28 at 17:58 -0800, Hollis Blanchard wrote:
> I have F16 here (NM 0.9.2) with a Beagleboard doing USB gadget 
> networking, and NM seems to be treating the wired and USB connections as 
> the same thing. After booting the Beagleboard, I get two "Wired" items 
> in the NM connection list, but they are sharing a single configuration. 
> This is a problem because I need to share my host's ethernet in order to 
> give the Beagleboard connectivity -- definitely not the same configuration.
> When I click the "+" button for a new configuration, my only option is VPN.
> 
> I'm sure I had this working in F14 or F15, but I can't remember how. Am 
> I missing something simple? Thanks!

Hi Hollis!

Do either of the interfaces have stable MAC addresses?  The usual
mechanism would be to lock connections to each of the MAC addresses of
the interfaces, so that you have connection #1 locked to onboard wired,
and connection #2 locked to USB, and then they are both set up
correctly.  Unfortunately, I think on the gadget stuff sometimes the MAC
address is random and then this becomes an excercise in creating udev
rules to set the MAC address to a well-known one.

Unfortunately, as I'm sure you know, device names are not stable; they
depend on bus topology and even module loading order.  I recently had a
bug where a module switched it's firmware loading scheme, delaying the
call to register_netdev() for a second or two, which caused another
network device to register itself first.  Fun times...  thus NM doesn't
allow locking connections to interface names.  (another aside: that
would have completely broken networking in the switch from F15 -> F16
where interface names are now created depending on the bus, slot, and
BIOS information).

Anyway, if you can get stable MAC addresses, then lock the connections
in nm-connection-editor to the MAC address of the interface and it
should work exactly as you expect.  Let me know how it goes.

Dan