On Wed, Dec 20, 2006 at 04:34:17PM +0100, Arjan van de Ven wrote:

5 seconds is unfair and unrealistic though. The *hardware* negotiation
before link is seen can easily take upto 45 seconds already.
That's a network topology/hardware issue (spanning tree fun) that
software or even the hardware in your PC can do nothing about.

It's about ergonomics, not technical capabilities or fairness.

this means that the "power up time" needs to be at least 45 seconds, if
it's then down 5 seconds inbetween... that's not real power savings.

Then that means you can't have usable autodetection and power savings
at the same time.  That's a pefectly acceptable answer, you just have
to give the choice between the two to the user.  From the kernel
p.o.v, it just means that you probably need 3 modes:
1- active and exchanging packets

2- inactive but waiting for plugging and able to tell something is
   going on fast (like 0.5s fast)

3- powered off

and they probably already exist (UP+addr/procmisc. set, UP and DOWN).
And if the second mode can't be lower power than the first, that's
just life.  An hypothetical mode 4 identical to 2 without the "fast"
part is just not worth bothering with.

  OG.