From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43928C678D4 for ; Thu, 2 Mar 2023 16:50:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230063AbjCBQua (ORCPT ); Thu, 2 Mar 2023 11:50:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230056AbjCBQu3 (ORCPT ); Thu, 2 Mar 2023 11:50:29 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79849D3 for ; Thu, 2 Mar 2023 08:50:07 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4FDEDB8121B for ; Thu, 2 Mar 2023 16:49:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9B50AC4339B; Thu, 2 Mar 2023 16:49:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1677775774; bh=rJSYZJupHT7cV7i8wdDq1MgG56MnrDYdgtRHNo0HNhc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=hqm7cfmJrzu5h5hndotBpozz5mWU19A1bduyfFAS/E1UJ068t4XDB3e/h8KC85TBo VSbVZrqdEarrg8QSj4zY/jxP7nXcXW3sy+JEhAhlYl52pVxh8toBrAjZn81FVp46+S haLGUgTFYnJMOfcr+vaMQrjFtZwAW+L5CR178NfeqUw1sgPAtaCPq2WsdKacNyNAoB SY4Cr/akYsuLY5HaA/lrAjlFfPyFJ28WuoIz1Xuhml3RM8cc0Qwl0Jcjc+KEAgpRoI YmByarvaiBVhYeKwTd6dl9BL4aSxf0tWDxqcR4rAyl5d+AHyQNexGczvOD56eLhajr UPb1Q+R8IC5tw== Date: Thu, 2 Mar 2023 08:49:32 -0800 From: Jakub Kicinski To: "Russell King (Oracle)" Cc: Richard Cochran , =?UTF-8?B?S8O2cnk=?= Maincent , andrew@lunn.ch, davem@davemloft.net, f.fainelli@gmail.com, hkallweit1@gmail.com, netdev@vger.kernel.org, Thomas Petazzoni , Maxime Chevallier Subject: Re: [PATCH RFC net-next] net: phy: add Marvell PHY PTP support [multicast/DSA issues] Message-ID: <20230302084932.4e242f71@kernel.org> In-Reply-To: References: <20230228141630.64d5ef63@kmaincent-XPS-13-7390> <20230228142648.408f26c4@kernel.org> <20230228145911.2df60a9f@kernel.org> <20230301170408.0cc0519d@kmaincent-XPS-13-7390> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 2 Mar 2023 11:49:26 +0000 Russell King (Oracle) wrote: > (In essence, because of all the noise when trying the Marvell PHY with > ptp4l, I came to the conlusion that NTP was a far better solution to > time synchronisation between machines than PTP would ever be due to > the nose induced by MDIO access. However, I should also state that I > basically gave up with PTP in the end because hardware support is > overall poor, and NTP just works - and I'd still have to run NTP for > the machines that have no PTP capabilities. PTP probably only makes > sense if one has a nice expensive grand master PTP clock on ones > network, and all the machines one wants to synchronise have decent > PTP implementations.) Don't wanna waste too much of your time with the questions since I haven't done much research but - wouldn't MAC timestamp be a better choice more often (as long as it's a real, to-spec PTP stamp)? Are we picking PHY for historical reasons? Not that flipping the default would address the problem of regressing some setups..