From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) (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 D2D682580D1 for ; Thu, 12 Feb 2026 18:40:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.85.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770921640; cv=none; b=Ay4BX+XKT3IVx6/m4NoxGDTsxgfqlVrDwuaRILVR09pNUIkWtwh4VBTFMMtkaVJAYTnH/G97V1gJD2PF6ukT9iw5nWe2uomxRGK6BxJlw12XwF/SqilgVvV9CiM112AH3lxSgfMHaGPccW49Luhv7E0WEl+0Gyw+QhHnJ9qSzaU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770921640; c=relaxed/simple; bh=AfFfEZZmykQNiWI1P7tQUCRv6W4BRKkmHedNGBEyn04=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=uMmiW327tSWzkqfN1RGhI5mTX1pmpwj4TIBkf9lxlmE0VbWSzHNwkoaP+78bHg6waW45gbUMfrR2MOakyEvpWUBlk3bjwTOhNQBrmS/0sFtOtuB93V7cX4qVpVGYocGZGrTm9DfN2N1iLWLkrAhikHuYUgHC0Qti2A2oypurFJY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=BghUVet7; arc=none smtp.client-ip=185.246.85.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="BghUVet7" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id EE9E54E40CDB; Thu, 12 Feb 2026 18:40:36 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id B3017606B8; Thu, 12 Feb 2026 18:40:36 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 30F8E103688A1; Thu, 12 Feb 2026 19:40:31 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1770921636; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:content-language:in-reply-to:references; bh=SQCxFGr5qrtRperceJYZ7ft+IVLPFCaXNx0EVEdG/1Y=; b=BghUVet7sXdsZQ150AryHSKKGXglYKMvbkzRKzQiWuIjZI7yDJM5Y8hz7KCwqP/0BfhfUv tYpiskuagrcm9K1taSmKYvjplipkxsJ+pWkEdnbH4xj/mjdPV0X/xTwzxOt1BrBUxioK9B FJ9sgXYrC8MVPAqlayR7H5rDr5OJPx4nc1dvaUHRUO2l9eqlopEEvaWtxOKff8oIz6Lynh 7lnQhDGx+Zw9G6PyqWJzobNdxlvgs/ohnA2tPbgZUTLhoysH/s1vh8PHUoAhxs47SAY5l3 9D2NPCjo5Y7PYmvTJN8aWz6JxzJO0ZZ7Ir4CuFbvu0aIlVwjv8Z0LejtJA1u9A== Message-ID: <5929eafb-6101-4570-beaf-ed08ae109423@bootlin.com> Date: Thu, 12 Feb 2026 19:40:30 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] net: phy: dp83869: Set auto mdix bit for forced 100Base-Tx mode To: Meghana Malladi , Andrew Lunn Cc: pabeni@redhat.com, kuba@kernel.org, edumazet@google.com, davem@davemloft.net, linux@armlinux.org.uk, hkallweit1@gmail.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, srk@ti.com, Vignesh Raghavendra , Roger Quadros , danishanwar@ti.com References: <20260211131033.2525617-1-m-malladi@ti.com> <0a9d0ec8-09c4-4029-8449-8c8f08c6dca0@lunn.ch> From: Maxime Chevallier Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 Hi Meghana, On 12/02/2026 07:21, Meghana Malladi wrote: > Hi Andrew, > > On 2/11/26 19:42, Andrew Lunn wrote: >> On Wed, Feb 11, 2026 at 06:40:32PM +0530, Meghana Malladi wrote: >>> When using DP83869 in force 100Base-Tx mode, the PHY is required >>> to have robust Auto-MDIX feature enabled from register 1Eh. >>> Refer to 7.4.1.2 100BASE-TX section in the TRM [1] for more details. >> >> What are the results of not enabling this? How would somebody know >> they need this patch? > > This is the fix for 100M full duplex when auto-neg gets disabled, it > fails to have a link up and this patch fixes it. I will add more > description to the commit message. I have a board here with a DP83869 + imx93's dwmac, but I couldn't trigger the bug locally. I forced speed, dpx and aneg settings with : ethtool -s eth0 speed 100 duplex full autoneg off I did the same on the link partner, but I was still able to get link-up. I'm not saying the bug isn't real, I mostly curious about the kind of circumstances that causes this prblem to show-up. Do you have any clarifications on that ? I'll be happy to give the fix a try, if I can manage to reproduce the issue :) Maxime