From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 263FFC4724C for ; Thu, 30 Apr 2020 20:51:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 022F920836 for ; Thu, 30 Apr 2020 20:51:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="czWxAQDK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726645AbgD3UvH (ORCPT ); Thu, 30 Apr 2020 16:51:07 -0400 Received: from vps0.lunn.ch ([185.16.172.187]:35036 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726338AbgD3UvG (ORCPT ); Thu, 30 Apr 2020 16:51:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=5A06G/vo4nsY8mFEkZch8Qvl2TNKsv7kBPwF2mP9QA0=; b=czWxAQDKv98MtAC8l9hWTbB2P4 60yl54BWYL88bQfGnbZaj1aOWOm1Z5wJhStMc5ixDNUyj+puM3/XB6iZgWm8hv39wKm1K0xjIddsB cy0MHsKPfEcEs2mk4Vzp5ACRLFZMsxP2EQDvXHGQQqCJj7keYsL75Q5+/MqegK+XYcOY=; Received: from andrew by vps0.lunn.ch with local (Exim 4.93) (envelope-from ) id 1jUG96-000SnX-JG; Thu, 30 Apr 2020 22:51:00 +0200 Date: Thu, 30 Apr 2020 22:51:00 +0200 From: Andrew Lunn To: Michael Walle Cc: cphealy@gmail.com, davem@davemloft.net, f.fainelli@gmail.com, hkallweit1@gmail.com, mkubecek@suse.cz, netdev@vger.kernel.org Subject: Re: [PATCH net-next v1 0/9] Ethernet Cable test support Message-ID: <20200430205100.GG107658@lunn.ch> References: <20200425180621.1140452-1-andrew@lunn.ch> <20200429160213.21777-1-michael@walle.cc> <20200429163247.GC66424@lunn.ch> <20200430182331.GE76972@lunn.ch> <30fd56d966b577a045ddeb01942a9944@walle.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <30fd56d966b577a045ddeb01942a9944@walle.cc> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Apr 30, 2020 at 09:44:12PM +0200, Michael Walle wrote: > Am 2020-04-30 20:23, schrieb Andrew Lunn: > > > Ok. I do have one problem. TDR works fine for the AR8031 and the > > > BCM54140 as long as there is no link partner, i.e. open cable, > > > shorted pairs etc. But as soon as there is a link partner and a > > > link, both PHYs return garbage. As far as I understand TDR, there > > > must not be a link, correct? > > > > Correct. > > > > The Marvell PHY will down the link and then wait 1.5 seconds before > > starting TDR, if you set a bit. I _think_ it downs the link by turning > > off autoneg. > > According to the Atheros datasheet the "CDT can be performed when > there is no link partner or when the link partner is auto-negotiating". > One could interpret that as is is only allowed _during_ autoneg. But > as far as I know there is no indication if autoneg is currently active, > is it? > > > Maybe there is some hints in 802.3 clause 22? > > I'm just skimming over that, but even if the link could be disabled > locally, shouldn't there still be link pulses from the peer? I guessing here.... If the local end stops negotiating, the link peer will stop sending traffic, and just sends link pulses. The PHY knows when the next set of link pulses are expected from the link partner, since they should be every 16ms. It can then avoid them when doing its TDR. Andrew