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From: Bill Fink <billfink@mindspring•com>
To: David Lamparter <equinox@diac24•net>
Cc: Ben Hutchings <bhutchings@solarflare•com>,
	Mahesh Bandewar <maheshb@google•com>,
	linux-netdev <netdev@vger•kernel.org>,
	Tom Herbert <therbert@google•com>,
	David Miller <davem@davemloft•net>
Subject: Re: [PATCH v2] ethtool : Allow ethtool to set interface in loopback mode.
Date: Sat, 4 Dec 2010 20:33:48 -0500	[thread overview]
Message-ID: <20101204203348.cf4fc883.billfink@mindspring.com> (raw)
In-Reply-To: <20101203164844.GB235120@jupiter.n2.diac24.net>

On Fri, 3 Dec 2010, David Lamparter wrote:

> On Fri, Dec 03, 2010 at 04:33:34PM +0000, Ben Hutchings wrote:
> > On Fri, 2010-12-03 at 17:03 +0100, David Lamparter wrote:
> > > On Thu, Dec 02, 2010 at 02:35:51PM -0800, Mahesh Bandewar wrote:
> > > > This patch adds -L command-line option to switch loopback mode on/off
> > > > and -l option to display current loopback mode on a specified interface.
> > > [...]
> > > > +.A1 on off
> > > > +Switches loopback mode
> > > > +.B on
> > > > +or
> > > > +.B off
> > > 
> > > What about devices that support different kinds of loopback, like MAC
> > > loopback & PHY loopback? (No idea if we have kernel support for this
> > > either...)
> > 
> > That distinction is useful for diagnostic purposes, but drivers can
> > already cover those different loopback modes in self-test.  The
> > motivation for this feature is testing data path behaviour, and Mahesh
> > has specified that loopback should be enabled as near as possible to the
> > host.
> 
> Ah, good enough. Thanks.

Perhaps in the future it could be extended, if desired,
to something like:

	loopback=0	disabled
	loopback=1	driver loopback nearest host
	loopback=2	driver loopback nearest network

Both types of loopback could be useful for different purposes.

					-Bill

      reply	other threads:[~2010-12-05  1:33 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-02  0:57 [PATCH] ethtool : Allow ethtool to set interface in loopback mode Mahesh Bandewar
2010-12-02 14:21 ` Ben Hutchings
2010-12-02 22:35   ` [PATCH v2] " Mahesh Bandewar
2010-12-03 16:03     ` David Lamparter
2010-12-03 16:33       ` Ben Hutchings
2010-12-03 16:48         ` David Lamparter
2010-12-05  1:33           ` Bill Fink [this message]

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