From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 31868111B4 for ; Wed, 17 May 2023 19:19:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 94156C433EF; Wed, 17 May 2023 19:19:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684351167; bh=pv57v+L5LwhleTIr9vC89uYE5ANrp9INSfimIZ+XJ/4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RGdwc8YTyeX6ejoPilPUlTpIA45HryV3udFORfyFUbsLAGgAFhzbaF9Ajl0SHrw8d ofoG7UTVzZEjUbf8ao96/KTEEJ9QY+zDCdPTw5Mixns5gazR3QI/bpR0RgRtPMr2+u pk4cadZZ7AJnoJm7LhfzqhhoKMhNSwR6f+hBl3G0CK67K693AYCLpkXbs3KZe3yUOt tdpYlG6aGD2AnQY1GS+mvH8A1RAXmmNBLTPtkfZb8JrJ1TG07coaPszUjA+JPyi7Fv 6+xhRTQZXYVCqfdhWMvTPd/lPoGL4r7rjJC1kS/vDkgc8NoaoMfrOrm+U0IgJgd9PE YajnSWAlQmWHg== Date: Wed, 17 May 2023 12:19:25 -0700 From: Jakub Kicinski To: Vladimir Oltean Cc: "Russell King (Oracle)" , Andrew Lunn , =?UTF-8?B?S8O2cnk=?= Maincent , netdev@vger.kernel.org, glipus@gmail.com, maxime.chevallier@bootlin.com, vadim.fedorenko@linux.dev, richardcochran@gmail.com, gerhard@engleder-embedded.com, thomas.petazzoni@bootlin.com, krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org Subject: Re: [PATCH net-next RFC v4 2/5] net: Expose available time stamping layers to user space. Message-ID: <20230517121925.518473aa@kernel.org> In-Reply-To: <20230512103852.64fd608b@kernel.org> References: <20230406173308.401924-1-kory.maincent@bootlin.com> <20230406173308.401924-3-kory.maincent@bootlin.com> <20230406184646.0c7c2ab1@kernel.org> <20230511203646.ihljeknxni77uu5j@skbuf> <54e14000-3fd7-47fa-aec3-ffc2bab2e991@lunn.ch> <20230511210237.nmjmcex47xadx6eo@skbuf> <20230511150902.57d9a437@kernel.org> <20230511230717.hg7gtrq5ppvuzmcx@skbuf> <20230511161625.2e3f0161@kernel.org> <20230512102911.qnosuqnzwbmlupg6@skbuf> <20230512103852.64fd608b@kernel.org> 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-Transfer-Encoding: 7bit On Fri, 12 May 2023 10:38:52 -0700 Jakub Kicinski wrote: > On Fri, 12 May 2023 13:29:11 +0300 Vladimir Oltean wrote: > > On Thu, May 11, 2023 at 04:16:25PM -0700, Jakub Kicinski wrote: > > > Oh, you should tell me, maybe off-list then. 'Cause I don't know any. > > > > I hope the examples given in private will make you reconsider the > > validity of my argument about DMA timestamps. > > I may have lost track of what the argument is. There are devices > which will provide a DMA stamp for Tx and Rx. We need an API that'll > inform the user about it. > > To be clear I'm talking about drivers which are already in the tree, > not opening the door for some shoddy new HW in. It dawned on me while reading a phylink discussion that I may have misunderstood the meaning of the MAC vs PHY time stamp sources. By the standard - stamping happens under the MAC, so MAC is the "right" place to stamp, not the PHY. And there can be multiple PHYs technically? Are we just using the MAC vs PHY thing as an implementation aid, to know which driver to send the request to? Shouldn't we use the clock ID instead?