From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [185.203.201.7]) (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 5794131A8F for ; Tue, 23 Apr 2024 07:08:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.203.201.7 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713856095; cv=none; b=gC4VvAtNwVd4dwJp8V5wFHD7lAF5/1840iuP29UpxTrDx6/56HPATiDHsRmS+/tsZ2u6dNdW+HsDOL63ZNy3AxOGaozIGDMOE37gA3VD2OGpjmTcQ5B6YzALKrUAMAmDCF+X0W8FJawusfLvBrA8dh3AZLPJYh10WVWq9Fkuwzw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713856095; c=relaxed/simple; bh=LbZv+IFW0ABDVGbIyrN2XXjy2qr1emVrakdBmUuQ5Q4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=bOS7NLGSP6B50c09JYY6oNbqlXAq6HiuDHVTBsT9A6SqIK759FBmFKxaxAP/LchofkYXCB2TPwFaFahgz3d7BjJXEhLVarzEHX3VxZqDJF2CeU0D3zQr1zVYRx7oRRPOoUz+dIDLUlf0/50R0X046Nv240FJo/31v8qs/OYQjy0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; arc=none smtp.client-ip=185.203.201.7 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rzAG2-0004PC-Fe; Tue, 23 Apr 2024 09:08:02 +0200 Received: from [2a0a:edc0:2:b01:1d::c5] (helo=pty.whiteo.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1rzAG0-00Dppn-33; Tue, 23 Apr 2024 09:08:00 +0200 Received: from ore by pty.whiteo.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1rzAFz-009lmk-3C; Tue, 23 Apr 2024 09:08:00 +0200 Date: Tue, 23 Apr 2024 09:07:59 +0200 From: Oleksij Rempel To: Richard Cochran Cc: Andrew Lunn , Alexandre Torgue , Jose Abreu , "David S. Miller" , Heiner Kallweit , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Maxime Coquelin , Woojung Huh , Arun Ramadoss , Russell King , kernel@pengutronix.de, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, UNGLinuxDriver@microchip.com, linux-stm32@st-md-mailman.stormreply.com Subject: Re: [PATCH net-next v1 2/4] net: phy: micrel: lan8841: set default PTP latency values Message-ID: References: <20240417164316.1755299-1-o.rempel@pengutronix.de> <20240417164316.1755299-3-o.rempel@pengutronix.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Hi Richard, On Thu, Apr 18, 2024 at 11:46:48PM -0700, Richard Cochran wrote: > On Wed, Apr 17, 2024 at 10:23:07PM +0200, Andrew Lunn wrote: > > I suggest you go read older messages from Richard. It was a discussion > > with Microchip about one of their PHYs. > > My 2 cents: > > User space has all of the hooks needed to configure corrections for a > given setup. > > Hard coding corrections in device drivers is bound to fail, based on > prior experience with Vendors not knowing or caring how their products > actually work. Vendors will publish value X one year, then delete the > info (to avoid embarrassment), then publish the new value Y, once > customers have forgotten about X. > > So, prudent users will always calibrate their beloved systems, not > trusting the Vendors to provide anything close to reasonable. > > Ergo, adding new magical correction in a kernel release causes > regressions for prudent users. > > But, in the end, that doesn't matter, because prudent users are used > to being abused by well-meaning yet misguided device driver authors. > > Prudent users are wise, and they will re-calibrate their systems > before rolling out an updated kernel. Ok, i see. Thank you for your feedback. Are the recommended FOSS projects managing calibration values per- linkmode/port/device in user space? What is recommended way for calibration? Using some recommended device? Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |