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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF486CCA473 for ; Fri, 22 Jul 2022 12:59:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234213AbiGVM7s (ORCPT ); Fri, 22 Jul 2022 08:59:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229704AbiGVM7q (ORCPT ); Fri, 22 Jul 2022 08:59:46 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CC4C57E07; Fri, 22 Jul 2022 05:59:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9B69261E84; Fri, 22 Jul 2022 12:59:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 466A1C341C6; Fri, 22 Jul 2022 12:59:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1658494785; bh=BKrizWV96d8+rZwIec8s+GHsD43ct+a/ytonnY3af3Y=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=TAIxnlQx4527e7gKVxmMg1IyqHmGp7XRatUsqJ/ANbfat2x0Ad5ap6wHnp2dNfFrb DYmhQmD0xL3CkWfA0X/VTddr/NosMCBZG7KXgUSNcb7WRDdeAp/I2YkzYYSiOu+n7Y V2cTtfkce9tmYGi3lYZqZPdjjHLxdbW8NbScXEcdh+5Hs0NZoeIjViekvD/r/cgxOR CgGDDglgNry2vcNHljiUSez3IS+uKG/G4sXv/rH5twGAFaYilVJoXWYczvPDhdKu6f jrp213JC37jLfc9Lvflko5MHOE5Ftw7xIYeeBxE9R9yCj53RMKI/kpr/bChYDb21me /AbxW+iqz3aFA== Date: Fri, 22 Jul 2022 14:59:36 +0200 From: Marek =?UTF-8?B?QmVow7pu?= To: Vladimir Oltean Cc: "Russell King (Oracle)" , Andrew Lunn , Heiner Kallweit , Alexandre Belloni , Alvin __ipraga , Andy Shevchenko , Claudiu Manoil , Daniel Scally , "David S. Miller" , DENG Qingfang , Eric Dumazet , Florian Fainelli , George McCollister , Greg Kroah-Hartman , Hauke Mehrtens , Heikki Krogerus , Jakub Kicinski , Kurt Kanzenbach , Landen Chao , Linus Walleij , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Matthias Brugger , netdev@vger.kernel.org, Paolo Abeni , "Rafael J. Wysocki" , Sakari Ailus , Sean Wang , UNGLinuxDriver@microchip.com, Vivien Didelot , Woojung Huh Subject: Re: [PATCH net-next 3/6] net: dsa: add support for retrieving the interface mode Message-ID: <20220722145936.497ac73f@dellmb> In-Reply-To: <20220721182216.z4vdaj4zfb6w3emo@skbuf> References: <20220716105711.bjsh763smf6bfjy2@skbuf> <20220716123608.chdzbvpinso546oh@skbuf> <20220720224447.ygoto4av7odsy2tj@skbuf> <20220721134618.axq3hmtckrumpoy6@skbuf> <20220721151533.3zomvnfogshk5ze3@skbuf> <20220721192145.1f327b2a@dellmb> <20220721192145.1f327b2a@dellmb> <20220721182216.z4vdaj4zfb6w3emo@skbuf> X-Mailer: Claws Mail 3.19.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 21 Jul 2022 21:22:16 +0300 Vladimir Oltean wrote: > On Thu, Jul 21, 2022 at 07:21:45PM +0200, Marek Beh=C3=BAn wrote: > > Marvell documentation says that 2500base-x does not implement inband > > AN. =20 >=20 > Does Marvell documentation actually call it 2500base-x when it says it > doesn't support in-band autoneg? Yes, it does. > > But when it was first implemented, for some reason it was thought that > > 2500base-x is just 1000base-x at 2.5x speed, and 1000base-x does > > support inband AN. Also it worked during tests for both switches and > > SOC NICs, so it was enabled. > >=20 > > At the time 2500base-x was not standardized. Now 2500base-x is > > stanradrized, and the standard says that 2500base-x does not support > > clause 37 AN. I guess this is because where it is used, it is intended > > to work with clause 73 AN somehow. =20 >=20 > When you say 2500base-x is standardized, do you mean there is a document > somewhere which I could use to read more about this? IEEE Std 802.3cb-2018: Amendment 1: Physical Layer Specifications and Management Parameters for 2.5 Gb/s and 5 Gb/s Operation over Backplane. Annex 127A (informative): Compatibility of 2.5GBASE-X PCS/PMA with 1000BASE-X PCS/PMA running 2.5 times faster ... This annex discusses the restrictions when operating 2.5GBASE-X PCS/PMA with a 1000BASE-X PCS/PMA link partner running 2.5 times faster. Compatibility of the PMD is outside the scope of this annex. In this annex when 1000BASE-X PCS/PMA is referred to, the 2.5 times speed up is implied. ... The 2.5GBASE-X PCS does not support Clause 37 Auto-Negotiation. Hence, the 1000BASE-X PCS is expected to have its Clause 37 Auto-Negotiation functionality disabled so that the /C/ ordered set will not be transmitted. If a 2.5GBASE-X PCS receives /C/ ordered set, then undefined behavior may occur. ... Marek