From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4B7BD1EF36E; Mon, 27 Jul 2026 20:18:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785183498; cv=none; b=e1V+GzGe663/luMJ5jcdXyOcnbBPyerSbfuNuP8KUCRM1LtoFCtc+jnc2w2R+ToD6LR5RFE3ylNwaThsOTPQahdHcp+n5pih4X1KKm0iv/lrxKnnsMUeFlcc5yGg5DM6DlRoyUEbzRztBfB8xxPd9HgjtVhK3Znj10qpY51SM4s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785183498; c=relaxed/simple; bh=OyZj/ONRG+egh0yHwE7tIaiXgJG3qrDSVWWLu9ja6ag=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Fr8Ru3QUwLIJ/V9iBjtU0EZoRgtGWdbrxmr0lgk22C/Gi2xFrBWzsWw1RrAg4DLH6OJh8Q2VuiGRhu6pO5AZ1U48zEJe2jFWCPF3cBsqa+ehVNaWeJlrFjNuNdVMf8wrfw09QE3NjqKEWQCz8LnFYaVNtlgLp4Bjc5K0DlZA8Kk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JxOUqduC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JxOUqduC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 686F21F000E9; Mon, 27 Jul 2026 20:18:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785183496; bh=TH5btLtsdzynlq0mS3tGP3AaHGFbiL62+K0Auf+4mbo=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=JxOUqduC4Qt4IjQwMvdftB93pWeXoO7vIqYAIoNniRnDLz8FwPK6i2gLj3cOAeHD1 Nm11Kb2nrxyigva2J9EeGV+CMXnKeRkw+R3zbVWcN9n6THongIvDwQRmAJuiogWyYU sce/QX893ELdrF1PIqNbntmLkZE9imc6uOzcHPQbwbOj3mib47ezRGH3XdoLkeca7m plRz/u1NtCjs5M7xKZnGFRj4PWxuIImRK3fJlmlLwdwhxMqV4E+cVXOhwlxhDsVRM9 g4h7VsuySsxReqCEsZf6mr+KXZ8WNpKYUKP+vR4q+3LIZ/z8TSHR33usIu74+9E0/S LT9da3WVPphPw== Date: Mon, 27 Jul 2026 13:18:15 -0700 From: Jakub Kicinski To: Andrew Lunn Cc: Luke Howard , Richard Cochran , Vladimir Oltean , "David S. Miller" , Eric Dumazet , Paolo Abeni , Vivien Didelot , Gregory CLEMENT , Cedric Jehasse , Kieran Tyrrell , Max Holtmann , Max Hunter , Christoph Mellauner , Simon Gapp , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v3 0/3] net: dsa: mv88e6xxx: various hwstamp fixes Message-ID: <20260727131815.0403cbb3@kernel.org> In-Reply-To: References: <20260719-mv88e6xxx-ptp-fixes-v3-0-161386ac8a62@padl.com> <20260724165207.6a03c9db@kernel.org> 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-Transfer-Encoding: 7bit On Sat, 25 Jul 2026 17:54:53 +0200 Andrew Lunn wrote: > On Fri, Jul 24, 2026 at 04:52:07PM -0700, Jakub Kicinski wrote: > > On Sun, 19 Jul 2026 15:30:52 +1000 Luke Howard wrote: > > > Three fixes for improving the reliably of hardware timestamp acquisition > > > on Marvell switches. In our tests this eliminated missed timestamps in > > > ptp4l, whilst also preserving PTP event and general message ordering on > > > switches that support embedded timestamps. > > > > Do you know if there's any precedent in the existing upstream drivers > > for overriding the reserved bytes? It's not normal for devices to modify > > the ingress frames. Perhaps there's some precedent, but if not I think > > we should gate this (eg with a devlink param?) > > > > Andrew, do you have any opinion? Or perhaps Richard? > > I have a dim memory of PHYs who change the packet by adding time > stamps. There are definitely DSA switches which can put the stamps in > the DSA header/trailer. Ack, thanks! To clarify I of course don't mind modification one-step timestamping style (Tx). But here we're overriding reserved protocol fields to carry local metadata (Rx). Let's see v4..