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 X-Spam-Level: X-Spam-Status: No, score=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBB20C433ED for ; Tue, 13 Apr 2021 10:51:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2C9961222 for ; Tue, 13 Apr 2021 10:51:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343968AbhDMKwN (ORCPT ); Tue, 13 Apr 2021 06:52:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236800AbhDMKwM (ORCPT ); Tue, 13 Apr 2021 06:52:12 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CC43C061574; Tue, 13 Apr 2021 03:51:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=AyA21hCwDZr44tPRW26rnzyhYZ7wNBvoep8VeScz3VQ=; b=KW64bWZPv7mAcY0rtoikq5GWu ZwntBdejvJO8lY/s7jHil3J4Iy4whTvPkfqiHdkhaxvWQmu0wOkY7T8Dy+8HFVhqAqfq9lQWdSN40 aJqawPMaZ5lNIQWk0qOUkd0G7JtNvGrEMqpK0JXyNZahhQ1Z6/1i8amynpR5UvVxqP4Skk1g8YSNY y990OmrYXF4OsnCjiJKqAMYNfQTjOAF92Mar/e81f/PVqz7PKHqEpz0IXwqVrrITNDkxOk1WCCA61 GqYJiG4UnrsNAgNvdLXLaf5MdPkKoXUkS2tut7LAozWehylPoGFtKwKvw7vHbWCt5Hn1ebzCLWGS9 vGntaCmUA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:52372) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lWGe2-0005Xz-Bj; Tue, 13 Apr 2021 11:51:46 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1lWGe0-00088B-CB; Tue, 13 Apr 2021 11:51:44 +0100 Date: Tue, 13 Apr 2021 11:51:44 +0100 From: Russell King - ARM Linux admin To: Lucas Stach Cc: Oleksij Rempel , Shawn Guo , Sascha Hauer , Andrew Lunn , Florian Fainelli , Heiner Kallweit , Philippe Schenker , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-imx@nxp.com, kernel@pengutronix.de, David Jander , Fabio Estevam , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2 0/7] remove different PHY fixups Message-ID: <20210413105144.GN1463@shell.armlinux.org.uk> References: <20210309112615.625-1-o.rempel@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: Russell King - ARM Linux admin Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Apr 13, 2021 at 12:00:45PM +0200, Lucas Stach wrote: > I agree with the opinion that those PHY fixups introduce more harm than > good. Essentially they are pushing board specific configuration values > into the PHY, without any checks that the fixup is even running on the > specific board it was targeted at. Yes and no. The problem is, that's an easy statement to make when one doesn't understand what they're all doing. Some are "board specific" in that the normal setup for e.g. iMX6 would be to enable clock output from the AR8035 PHY and feed that into the iMX6 - as far as I'm aware, that's the only working configuration for that SoC and PHY. However, it's also true that this fixup should not be applied unconditionally. Then there's SmartEEE - it has been found that the PHY defaults for this lead to link drops independent of the board and SoC that it is connected to. It seems that the PHY is essentially broken - it powers up with SmartEEE enabled, and when connected to another SmartEEE supporting device, it seems guaranteed that it will result in link drops in its default configuration. Freescale's approach has apparently been to unconditionally disable SmartEEE for all their platforms because of this. With a bit of research however (as has been done by Jon and myself) we've found that increasing the Tw parameter for 1G connections results in a much more stable link. So, just saying that these are bad without actually understanding what they are doing is _also_ bad. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!