From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (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 5732E1E1DE9; Thu, 17 Jul 2025 17:30:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752773420; cv=none; b=PWMLCB4cPeD/c++muI3N/aefYGnyo4CuzZW6kBfSzGEsWfUjeumSZf58dpbqiB+/klszWfIDJqrZ6iTIX0K/jCqI/0Cq0MADQxTozJIIeCuFVeCEEKFwtTQSadKcV8TY+nNyRuBSvvP7BJw8yo6Hw14g2NpixSBM6bug8J41o2c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752773420; c=relaxed/simple; bh=UerManGgtELtM2J88n+DiWg2YWAjMOuHu8daAdvjOrY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WqYK/qwci7PJMhCGbP/o97KJtpqjBA+fSulMVwCoBwsR3TlY7nOIQ4azrlj77QlbN2FaZJzoeU6A1KmjMBDLla/ZbB6flJVmQRR+G2m1DvLqMcsiSvbtRF56FoUMeqEfxOLTKSAhKNF2xdOD3s6XQnEBdqm2CrrT98cmdWHJwVQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=OBiT+uH9; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="OBiT+uH9" 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-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: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=nYpSzj4evXjvFbftiLWrnsC5l75ywYOdqG1UqGqr6bU=; b=OBiT+uH9MqG6iunp7Xp895LSqE BpepnI9LWCcZ+Uup0z+CkeiTMR1F2vfIfkpR2SaeUzo8RjB47ow7CqUWT4jDoBc9pM1YGdEcBRGp4 Wxc2S1OKL5iVRbe3BMVhkF62L6NGUrb9sT5oWuxLpfyIw73rmEhfRiF/vhfVwvVXFTRkeL1z5087o BlOL7kqRFlB/rfwf6Fb2rlzvJCx/N7Hxyq9rA9gLE3CXJfeCY428nC69UC+ZMXonFG1zVz0SuNftK mxb7ouz3tJOnU8OnE+ZZ8NAosNUcNPGbeC9o0Q3PZg6JjvrBjNrg9s6quay2FDk3jT0J6AK8IKVNH 88hkamxw==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:58238) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1ucSQg-0001Yk-2p; Thu, 17 Jul 2025 18:29:59 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.96) (envelope-from ) id 1ucSQb-0002JW-2M; Thu, 17 Jul 2025 18:29:53 +0100 Date: Thu, 17 Jul 2025 18:29:53 +0100 From: "Russell King (Oracle)" To: Oleksij Rempel Cc: Andrew Lunn , Heiner Kallweit , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Rob Herring , Krzysztof Kozlowski , Florian Fainelli , Maxime Chevallier , Kory Maincent , Lukasz Majewski , Jonathan Corbet , kernel@pengutronix.de, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Divya.Koppera@microchip.com Subject: Re: [PATCH net-next v1 1/1] Documentation: networking: add detailed guide on Ethernet flow control configuration Message-ID: References: <20250717103702.2112988-1-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: netdev@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: <20250717103702.2112988-1-o.rempel@pengutronix.de> Sender: Russell King (Oracle) On Thu, Jul 17, 2025 at 12:37:02PM +0200, Oleksij Rempel wrote: > +Changing the Settings > +--------------------- > +Use `ethtool -A ` to change the settings. > + > +.. code-block:: bash > + > + # Enable RX and TX pause, with autonegotiation > + ethtool -A eth0 autoneg on rx on tx on > + > + # Force RX pause on, TX pause off, without autonegotiation > + ethtool -A eth0 autoneg off rx on tx off > + > +**Key Configuration Concepts**: > + > +* **Autonegotiation Mode**: The recommended mode. The driver programs the PHY > + to *advertise* the `rx` and `tx` capabilities. The final active state is > + determined by what both sides of the link agree on. I'm not sure one cal call this "recommended mode", because it doesn't. If one specifies tx=0 rx=1, one would expect that the "recommend mode" would be tx=0 and rx=1, but if the link partner supports symmetric pause, you actually end up with tx=1 and rx=1. If the link partner supports only asymmetric, then you end up with tx=0 rx=1 as requested. Perversely, if you specify tx=1 rx=1, then if the remote supports only asymmetric, you end up with everything disabled. Only tx=1 rx=1 is supported in this configuration, you can't end up with anything else. Basically, I don't think calling it "recommended" works. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!