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Date: Wed, 18 May 2005 16:37:12 +0200
From: Max Kellermann <max@duempel.org>
To: linux-kernel@vger.kernel.org
Subject: Re: Detecting link up
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On 2005/05/18 13:40, Martin Zwickel <martin.zwickel@technotrend.de> wrote:
> On Wed, 18 May 2005 11:35:12 +0100
> Filipe Abrantes <fla@inescporto.pt> bubbled:
> > I need to detect when an interface (wired ethernet) has link up/down.
> > Is  there a system signal which is sent when this happens? What is the
> > best  way to this programatically?
> 
> mii-tool?

A thought on a related topic:

When a NIC driver knows that there is no link, why does it even try to
transmit a packet? It could return immediately with an error code,
without applications having to wait for a timeout.

(I had a quick peek at two drivers, and they don't check the link
status)

Max