From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: [patch net-next-2.6 1/2] net: allow to change carrier via sysfs Date: Thu, 1 Sep 2011 07:44:22 +0200 Message-ID: <20110901054420.GA1969@minipsycho> References: <1314715608-978-1-git-send-email-jpirko@redhat.com> <1314715608-978-2-git-send-email-jpirko@redhat.com> <20110831082655.GB2010@minipsycho.brq.redhat.com> <20110831084511.GD2010@minipsycho.brq.redhat.com> <4E5E939C.5000009@gmail.com> <1314821537.3274.24.camel@bwh-desktop> <4E5E9A30.1040105@gmail.com> <4E5E9E16.6060502@candelatech.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Nicolas de =?iso-8859-1?Q?Peslo=FCan?= , Ben Hutchings , =?utf-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , netdev@vger.kernel.org, davem@davemloft.net, eric.dumazet@gmail.com, shemminger@vyatta.com To: Ben Greear Return-path: Received: from mx1.redhat.com ([209.132.183.28]:53663 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751286Ab1IAFo3 (ORCPT ); Thu, 1 Sep 2011 01:44:29 -0400 Content-Disposition: inline In-Reply-To: <4E5E9E16.6060502@candelatech.com> Sender: netdev-owner@vger.kernel.org List-ID: Wed, Aug 31, 2011 at 10:48:22PM CEST, greearb@candelatech.com wrote: >On 08/31/2011 01:31 PM, Nicolas de Peslo=FCan wrote: >>Le 31/08/2011 22:12, Ben Hutchings a =E9crit : >>>On Wed, 2011-08-31 at 22:03 +0200, Nicolas de Peslo=FCan wrote: >>>>Le 31/08/2011 10:45, Jiri Pirko a =E9crit : >>>> >>>>>>>>Do you expect drivers using implementation different than just = calling >>>>>>>>netif_carrier_on/off? Or is it supposed to also e.g. power down= PHYs? >>>>>>>Yes, generally it can be used also for en/disable phy, for testi= ng >>>>>>>purposes if hw and driver would support it. >>>>>> >>>>>>I'd like to see this working for GRE tunnel devices (for keepaliv= e >>>>>>daemon to be able to indicate to routing daemons whether tunnel i= s >>>>>>really working) - implementation would be identical to dummy's ca= se. >>>>>>Should I prepare a patch or can I leave it to you? >>>>> >>>>>Ok, I can include it to this patchset (I'm going to repost first p= atch >>>>>anyway) >>>> >>>>Can't we assume that the dummy's case is the default behavior and >>>>register this default >>>>ndo_change_carrier callback for every device ? >>> >>>You have got to be joking. No device driver that has real link >>>monitoring should use this implementation. >> >>Well, why not? Arguably, this is probably not the feature one would u= se every day, but... >> >>Testing a cluster reaction to a link down event would be easier if on= e doesn't need to unplug the cable for the test. I understand that one = can turn off the >>switch port (physical or virtual), but echo 0 > /sys/class/net/eth0/c= arrier would be nice too. > >There is special hardware out there that can do bypass, and often it a= lso has a mode >that will programatically cut link by throwing some relays. We use th= is for our >testing equipment... > >If there is some way to twiddle standard-ish hardware to actually drop= link, that >would be neat. I'd think it should be an ethtool type of thing, howev= er. Ethtool can implement this eventually by calling the same ndo. > >Actually dropping link, and letting that naturally propagate up the st= ack seems >more reasonable than lying about the status half way up the stack. Yes, that is really the intension of the proposed ndo. Real hw driver should implement that as you say, not directly setting carrier_on/off > >Thanks, >Ben > >--=20 >Ben Greear >Candela Technologies Inc http://www.candelatech.com