From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 48DE26281E; Mon, 29 Jan 2024 13:13:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706534024; cv=none; b=uLmHLROvrSO9htLhylWGi4meaERpQJDy1ic+61xUkdcv/FOCKJLRyqBiv0h5M26ID2ybiYiWKAaDYLuWY/cn8qCqaNwohFze3FHoDUciw6PMgRzo/Ohcuqna7ishouF5lDJxszMSZJKFJlu1bQLVubz9Die4d8Mf76x3Vtc4Q9s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706534024; c=relaxed/simple; bh=1A2kwv15wQygVVOoqucjQOG6yZvrsKLSOxdqdrtflpo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=WgNVtu48PSlitj169KMOH2Ucatxx1ZYmcRrlsgYRG+tzla23/WaiE83XgzJuZkgItqy2eKH/g2T5oZBbT5IrVgCEz5i9GskFcEcYEZXtN6HGGRIcyJfrLotPJxw/ZkRBGLOlQrLs7f7glaRkBK5ofo+r/mmNPM15B6EQ8f5KwAI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=Lks3LUW5; arc=none smtp.client-ip=198.175.65.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="Lks3LUW5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1706534024; x=1738070024; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=1A2kwv15wQygVVOoqucjQOG6yZvrsKLSOxdqdrtflpo=; b=Lks3LUW5kikOTYIsZHogC66eDYYP+quAz/YTIE6ggUGSheUDKfFESczK f6+EcvBj0ftXVaKDQ0g5hiJ3hb5PKgvBN44CNL2NsCnwTOJDIfp4S+lJh ndtOJZaWVy1rLqk7m/aFTxFuzyqIniFU3SbUp8dZ5fqXZ7ufavUWpgQzg VsDHsWLeAMJrt59bBKBu0k+w9ufC+Qmufs2DPeHMCEHX9iH6gQxvjco7q 6hAkVODIP2F2HxeBY8jksoHNbs3c/SBZ/e1F5YMy0IgBp9aDZRSRdqveT bX+oTJZI4iFWED+vOZdansj5dSjzxvRUOaPyQqrMaaBIbbkH3ZQf/tC5Y g==; X-IronPort-AV: E=McAfee;i="6600,9927,10967"; a="10328513" X-IronPort-AV: E=Sophos;i="6.05,227,1701158400"; d="scan'208";a="10328513" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orvoesa104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jan 2024 05:13:43 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10967"; a="878068306" X-IronPort-AV: E=Sophos;i="6.05,227,1701158400"; d="scan'208";a="878068306" Received: from choongyo-mobl.gar.corp.intel.com (HELO [10.247.122.111]) ([10.247.122.111]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jan 2024 05:13:28 -0800 Message-ID: <41f08e94-3a0b-442b-be79-d30579f3e12d@linux.intel.com> Date: Mon, 29 Jan 2024 21:13:28 +0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v3 0/5] TSN auto negotiation between 1G and 2.5G Content-Language: en-US To: "Russell King (Oracle)" , Andrew Lunn Cc: Rajneesh Bhardwaj , David E Box , Hans de Goede , Mark Gross , Jose Abreu , Heiner Kallweit , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , =?UTF-8?Q?Marek_Beh=C3=BAn?= , Jean Delvare , Guenter Roeck , Giuseppe Cavallaro , Alexandre Torgue , Jose Abreu , Maxime Coquelin , Richard Cochran , Philipp Zabel , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Wong Vee Khee , Jon Hunter , Jesse Brandeburg , Revanth Kumar Uppala , Shenwei Wang , Andrey Konovalov , Jochen Henneberg , David E Box , Andrew Halaney , Simon Horman , Bartosz Golaszewski , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, platform-driver-x86@vger.kernel.org, linux-hwmon@vger.kernel.org, bpf@vger.kernel.org, Voon Wei Feng , Tan Tee Min , Michael Sit Wei Hong , Lai Peter Jun Ann References: <20230921121946.3025771-1-yong.liang.choong@linux.intel.com> <4caade36-d4be-4670-ac79-d9d00488293d@lunn.ch> From: Choong Yong Liang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 21/9/2023 10:09 pm, Russell King (Oracle) wrote: > On Thu, Sep 21, 2023 at 03:14:59PM +0200, Andrew Lunn wrote: >>> Auto-negotiation between 10, 100, 1000Mbps will use >>> in-band auto negotiation. Auto-negotiation between 10/100/1000Mbps and >>> 2.5Gbps will work as the following proposed flow, the stmmac driver reads >>> the PHY link status registers then identifies the negotiated speed. >> >> I don't think you replied to my comment. >> >> in-band is just an optimisation. It in theory allows you to avoid a >> software path, the PHY driver talking to the MAC driver about the PHY >> status. As an optimisation, it is optional. Linux has the software >> path and the MAC driver you are using basically has it implemented. > > Sorry Andrew, I have to disagree. It isn't always optional - there are > PHYs out there where they won't pass data until the in-band exchange > has completed. If you try to operate out-of-band without the PHY being > told that is the case, and program the MAC/PCS end not to respond to > the in-band frames from the PHY, the PHY will report link up as normal > (since it reports the media side), but no data will flow because the > MAC facing side of the PHY hasn't completed. > > The only exception are PHYs that default to in-band but have an inband > bypass mode also enabled to cover the case where the MAC/PCS doesn't > respond to the inband messages. > Russell is correct, we did set out-of-band for PCS and configured MAC. Due to the PHY not being completed, there will be no data flow through.