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 7036A3D3CE4; Tue, 31 Mar 2026 11:32:18 +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=1774956740; cv=none; b=tAfcdFuZs8nRPcgFpLxOSeby7nYy05axmGVmmg5rCWG5ybe7PBQi+wgH6Ks57dw6GwChvN1LXD11zqdiTOQRGKlk6s2bRRem7CeFp99EcPS1OHb2gx72MVsWhH4GBiPpUPJ4cwWSnCxfDWHZiPKhC5u8BTVJ6q8WvWE8BpeoBdU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774956740; c=relaxed/simple; bh=uWvD8OMz4WC6x8GO3aWXa1F6pahPRvU98JbiBGw9yDo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qpc2dpEx5t0FSjiu9Q4EGkkfPUya2AXf54C/bCGl37lNF3d4wR2241Oe9B9FGMChYSZ/bk+e/Gfso25oD/oXsqvYCotQSPeHMe0VfojbOWeb+zjV2SdZhr8NiX+GDc7b3yuBGHFhmoAypji2VJQVPe3Nl56WGGoGAi3rehr99S4= 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=fxiRpoKY; 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="fxiRpoKY" 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=uYqtW2F2Ni5winkOH9lfGjwrb6edTSs5jBu1jVMFlSA=; b=fxiRpoKYc5IcBtR6cQgCbX/6fF YSHWIeRlno1ZwSdI9vFVFueOGbrTzr+uBfSZfy3ni2s3e6aGqLgO3VD7NnrX0eT+r1SrchJpIZB39 FVBvOms9vBQPzft3rZZQOaXM2b5mx8Pr/q2A4xKNOoWpFgInoQ9TfccOu8/OyJJl5m/KTFjVaI4fL g5YvjmGMXmpo89tLtjxbwINFf/vDLUSoRzQOk22lqkDNG/vaD8per6Q1nxCeP3I3IJ78qPc25uCQG HoAbz/fkLQes6POSajIRpC+fMZL6xz9La+rap6bjd65VV2x3ZgEh8vOB1Qi0CWufRh9uIo8FwDcsu eW7qTjbQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:45026) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1w7XKS-000000001m6-1D5V; Tue, 31 Mar 2026 12:32:16 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1w7XKQ-000000003gP-48P0; Tue, 31 Mar 2026 12:32:15 +0100 Date: Tue, 31 Mar 2026 12:32:14 +0100 From: "Russell King (Oracle)" To: Nicolai Buchwitz Cc: netdev@vger.kernel.org, Phil Elwell , Andrew Lunn , Heiner Kallweit , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] net: phy: microchip: enable downshift by default on LAN88xx Message-ID: References: <20260330224630.579937-1-nb@tipi-net.de> <20260330224630.579937-3-nb@tipi-net.de> 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: <20260330224630.579937-3-nb@tipi-net.de> Sender: Russell King (Oracle) On Tue, Mar 31, 2026 at 12:46:27AM +0200, Nicolai Buchwitz wrote: > Enable auto-downshift from 1000BASE-T to 100BASE-TX after 2 failed > auto-negotiation attempts by default. This ensures that links with > faulty or missing cable pairs (C and D) fall back to 100Mbps without > requiring userspace configuration. > > Users can override or disable downshift at runtime: > > ethtool --set-phy-tunable eth0 downshift off > > Signed-off-by: Nicolai Buchwitz > Reviewed-by: Andrew Lunn I'm slightly concerned by this commit. ->config_init() is called when the netdev attaches the PHY, and also during the resume path - and it's the second one which I believe is a problem here. If the user has configured the downshift, it is reasonable for the user to expect the setting to be preserved over a suspend/resume. However, by placing this code in ->config_init(), you will overwrite the user's setting when the system resumes. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!