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 C2C4CC433EF for ; Sun, 6 Feb 2022 17:18:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344022AbiBFRSi (ORCPT ); Sun, 6 Feb 2022 12:18:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57572 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230187AbiBFRSg (ORCPT ); Sun, 6 Feb 2022 12:18:36 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84734C06173B; Sun, 6 Feb 2022 09:18:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To: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=WZawEW9E5ypY6Rh387lFEt31JC2J35mGwrAMc0/AAzo=; b=XzNSINIBxMQVdoTpXXnrPQzf2q pk211w38Qs3kErnL+k8t7syiQ5zoeirAlUJzTwt8Pa9w4ZsO1Q3czT///aWzv7KhIoCecbc2T1dX4 sjLBD4lghAlPv2APe5J7BKKvuLm3XrBMLH4Eu944Sdxm+MUow+GPxxZuB18qF4hLE3cGvLXfGnzXs QD1nvXzPzUX1jbTLT2bjSfxfuhBGI9gQ7wZBi1lNKWSiuAye/avfUJ898gwSmhNRXsRy2CJxNHXsm ZTjfU1x3MY16/PXPNMnO7py0r3uzDheMhlQYjjPXtjhf1N3lH4RyYMcosQcRnwBHcNOS4qfrs/K+7 MGhNDhOQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57066) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1nGlBA-0000Ad-EQ; Sun, 06 Feb 2022 17:18:24 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1nGlB6-00073Y-AG; Sun, 06 Feb 2022 17:18:20 +0000 Date: Sun, 6 Feb 2022 17:18:20 +0000 From: "Russell King (Oracle)" To: Raag Jadav Cc: Andrew Lunn , Heiner Kallweit , "David S. Miller" , Jakub Kicinski , Steen Hegelund , Bjarni Jonasson , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: phy: mscc: enable MAC SerDes autonegotiation Message-ID: References: <1644043492-31307-1-git-send-email-raagjadav@gmail.com> <20220206171234.GA5778@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220206171234.GA5778@localhost> Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 06, 2022 at 10:42:34PM +0530, Raag Jadav wrote: > Once the PHY auto-negotiates parameters such as speed and duplex mode > with its link partner over the copper link as per IEEE 802.3 Clause 27, > the link partner’s capabilities are then transferred by PHY to MAC > over 1000BASE-X or SGMII link using the auto-negotiation functionality > defined in IEEE 802.3z Clause 37. This is slightly incorrect. 1000BASE-X is only capable of operating at gigabit speed, not at 100M or 10M. The PHY _might_ signal the copper side pause resolution via the 1000BASE-X negotiation word, and even rarer would be whether operating at 1G FD or 1G HD. Out of the two, only SGMII is capable of operating at 1G, 100M and 10M, FD or HD. No pause resolution is passed. SGMII is not an 802.3 defined protocol, it's an adaption of 1000BASE-X by Cisco. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!