From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from vps0.lunn.ch (vps0.lunn.ch [156.67.10.101]) (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 DDF741D8A16; Tue, 7 Jan 2025 16:22:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=156.67.10.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736266978; cv=none; b=SkGUhSuOuKHQmqeKwR0qr5Ik3DWbgyiJWyPBizOhUKIQ4J8Sox0uDVloey39cN9kOQIhwpW15KBJhHhmU79s9rOnZVdYGTIy7g2Sn/bn0XGl/FjY5f0BDUv8zET7jgsJ3Vyqd5o/1PA0OKkoWztgsTRjShGguXMU+SERL+jv1WY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736266978; c=relaxed/simple; bh=upFMXhvCgcIcthR6rb9m6dyv+il0TE1oSMQE57Q2gVg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VA9+9uTRb5+Ekx51DnTkXKuiaLBdCpQ8HKNmpnUd2l3VoLMftwRB5gt+dXadVgZWmN8zSHg5Oij8Uky6QNll9YEUB11055Wi5S1QmLcAzquJaH++3qMiw+/xLskZg4IK49K5byGIFd0qHlmZgMwgOsEohzYnEH4PSPFY92e8aFU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch; spf=pass smtp.mailfrom=lunn.ch; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b=w0tGPoVP; arc=none smtp.client-ip=156.67.10.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lunn.ch Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="w0tGPoVP" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=agNC8oF9rUXSC9YbiyboPCaucWw3KQBsHEsPHpHMHUk=; b=w0tGPoVPuCFhfdKT9EhePXNdrJ 6jg0NeIr0AUvVSvAQgz6RgYSMfSxiav2wf1dQcn7Pvg6mulrK5TeyeZb6QwWc7qgTohB0O1VlXn0D 2p/O2XFLE7LMSp6+glS+sgUWj2LcyBQLUvEQPYKiwsR2+g0rQ16MT89SVZwSZFbFAwaw=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1tVCLz-002HvG-1C; Tue, 07 Jan 2025 17:22:51 +0100 Date: Tue, 7 Jan 2025 17:22:51 +0100 From: Andrew Lunn To: Maxime Chevallier Cc: "Russell King (Oracle)" , Kory Maincent , Oleksij Rempel , davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com, Jakub Kicinski , Eric Dumazet , Paolo Abeni , linux-arm-kernel@lists.infradead.org, Christophe Leroy , Herve Codina , Florian Fainelli , Heiner Kallweit , Vladimir Oltean , Marek =?iso-8859-1?Q?Beh=FAn?= , =?iso-8859-1?Q?Nicol=F2?= Veronese , Simon Horman , mwojtas@chromium.org, Antoine Tenart Subject: Re: [PATCH net-next RFC 0/5] net: phy: Introduce a port representation Message-ID: <601067b3-2f8a-4080-9141-84a069db276e@lunn.ch> References: <20241220201506.2791940-1-maxime.chevallier@bootlin.com> <20250107142605.6c605eaf@kmaincent-XPS-13-7390> <20250107171507.06908d71@fedora.home> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250107171507.06908d71@fedora.home> > I have however seen devices that have a 1G PHY connected to a RJ45 > port with 2 lanes only, thus limiting the max achievable speed to 100M. > Here, we would explicietly describe the port has having 2 lanes. Some PHYs would handle this via downshift, detecting that some pairs are broken, and then dropping down to 100M on their own. So it is not always necessary to have a board property, at least not for data. I've no idea how this affects power transfer. Can the link partners detect which pairs are actually wired? Andrew