On 2007-09-06 18:18 +0100, Paul Fidler wrote:
> 
> After a bit more investigating, I think udev is the reason the libertas
> driver claimed to create eth0 when, on my Balloon, it actually created eth3.
> 
> There is a file in /etc/udev/rules.d calls z25_persistent_net.rules. In
> the absence of any other persistent naming rules, udev itself (via the
> scripts in /lib/udev) writes to this file every time it finds a new
> network device (new MAC address). On my Balloon the z25_... file already
> had entries for three PlusCom devices as eth0..eth2, so when it created
> a new rule it labelled it as eth3, even though I've rebooted and there's
> no PlusCom device in sight.
> 
> So on the plus side, I think the libertas driver is doing the right thing
> and probably did create a network device called eth0, which udev then
> renamed.
> 
> On the minus side, this means that udev as supplied by Debian (Etch) can
> right to /etc during boot, if you have harware it hasn't seen before. This
> may have an implication for checkpointing...

OK. Yes. I have just exerienced this problem too. plug in 4 different
usb/ethernet adaptors and I get up to eth4.

Of course if multiple devices are plugged into a hub then numbering
them differently is argumably correct and if you have a wireless cf
card and a USB eth device then giving those different numbers is also
correct. 

However in the normal case of just one device, of whatever type, then
making that always eth0 is what we want. Most people will not have a
great pile of devices so this may not be too much of a problem in
practice. Changing the udev rules to not remember now-unplugged
devices would give the behaviour we want, I think. For now I'll just
make eth0 and eth1 have the default network config (dhcp+fallback to
fixed IP). 

Wookey
-- 
Principal hats:  Balloonz - Toby Churchill - Aleph One - Debian
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