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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 2B75FC433DB for ; Mon, 8 Feb 2021 20:28:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECD2064E54 for ; Mon, 8 Feb 2021 20:28:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236853AbhBHU1u (ORCPT ); Mon, 8 Feb 2021 15:27:50 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:56082 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235826AbhBHTEg (ORCPT ); Mon, 8 Feb 2021 14:04:36 -0500 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1l9Bou-004vFh-KW; Mon, 08 Feb 2021 20:03:36 +0100 Date: Mon, 8 Feb 2021 20:03:36 +0100 From: Andrew Lunn To: Serge Semin Cc: Serge Semin , Giuseppe Cavallaro , Alexandre Torgue , Jose Abreu , "David S. Miller" , Jakub Kicinski , Joao Pinto , Jose Abreu , Heiner Kallweit , Russell King , Alexey Malahov , Pavel Parkhomenko , Vyacheslav Mitrofanov , Maxime Coquelin , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 01/20] net: phy: realtek: Fix events detection failure in LPI mode Message-ID: References: <20210208140341.9271-1-Sergey.Semin@baikalelectronics.ru> <20210208140341.9271-2-Sergey.Semin@baikalelectronics.ru> <20210208174441.z4nnugkaadhmgnum@mobilestation> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210208174441.z4nnugkaadhmgnum@mobilestation> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Hi Andrew, > > I honestly tried to find any doc with a glimpse of errata for RTL8211E > PHY, but with no luck. Official datasheet didn't have any info regarding > possible hw bugs too. Thus I had no choice but to find a fix of the > problem myself. > > It took me some time to figure out why the events weren't reported after > the very first link setup (turned out only a full HW reset clears the > PC1R.10 bit state). I thought it could have been connected with some > sleep/idle/power-safe mode. So I disabled the EEE initialization in the > STMMAC driver. It worked. Then I left the EEE mode enabled, but called the > phy_init_eee(phy, 0) method with "clk_stop_enable==0", so PHY wouldn't > stop RXC in LPI mode. And it wonderfully worked. Then I started to dig in > from another side. I left "RXC disable in LPI" mode enabled and tried to > figure out what was going on with the PHY when it stopped reporting events > just by reading from its CSR using phytool utility. It was curious to > discover that any attempt to read from any PHY register caused the problem > disappearance (LED2 started blinking, events got to be reported). Since I > did nothing but a mere reading from a random even EEE-unrelated register I > inferred that the problem must be in some HW/PHY bug. That's how I've got > to the patch introduced here. If you have any better idea what could be a > reason of that weird behavior I'd be glad to test it out on my device. It is a reasonable explanation, and a read should not do any harm. Reviewed-by: Andrew Lunn Andrew 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=-9.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 6A2F0C433DB for ; Mon, 8 Feb 2021 19:05:03 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 02AB864E59 for ; Mon, 8 Feb 2021 19:05:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 02AB864E59 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lunn.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=w4dcEDuRsdGHcUqzVuSOvgNZ4I1Ney5OXDlNjfY04l4=; b=Zc0h8sdGD+Ix0oRL/si3re5hO u7nCo5/CbXCMFQA9va/E2r37euM0l0r04ZQnUbop32s8AzUS8gJivMZzlrkEDSGrQ0ry5fpkB1l5o 36jA4Kw30Oc4JMwdH/35/5cfN59JKWqOMVWjo2avkAEHmVYYwREQ3iblSMLG5NKDVaI82M/kO0WQn FeWjNcb38ieb7w+9WYv+lfD5ADtwyPXBvyYjgDUcZmPVjWJsdcMfeaxZUWI/apr538BNlY3BEmBHo R69wmawTSGygke0spgMtc6ydpPOAwsUCES7S1rpdVozAL9swGsnN7O0OupcwZLG7VhsG6cc3edW+h qf6LYC/7w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9BpD-0002lX-J8; Mon, 08 Feb 2021 19:03:55 +0000 Received: from vps0.lunn.ch ([185.16.172.187]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9BpA-0002kV-KL for linux-arm-kernel@lists.infradead.org; Mon, 08 Feb 2021 19:03:53 +0000 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1l9Bou-004vFh-KW; Mon, 08 Feb 2021 20:03:36 +0100 Date: Mon, 8 Feb 2021 20:03:36 +0100 From: Andrew Lunn To: Serge Semin Subject: Re: [PATCH 01/20] net: phy: realtek: Fix events detection failure in LPI mode Message-ID: References: <20210208140341.9271-1-Sergey.Semin@baikalelectronics.ru> <20210208140341.9271-2-Sergey.Semin@baikalelectronics.ru> <20210208174441.z4nnugkaadhmgnum@mobilestation> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210208174441.z4nnugkaadhmgnum@mobilestation> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210208_140352_698690_BD9352CA X-CRM114-Status: GOOD ( 16.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jose Abreu , Joao Pinto , linux-kernel@vger.kernel.org, Alexandre Torgue , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, Russell King , Serge Semin , Alexey Malahov , Jose Abreu , Pavel Parkhomenko , Maxime Coquelin , Jakub Kicinski , Giuseppe Cavallaro , Vyacheslav Mitrofanov , "David S. Miller" , linux-arm-kernel@lists.infradead.org, Heiner Kallweit Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org > Hi Andrew, > > I honestly tried to find any doc with a glimpse of errata for RTL8211E > PHY, but with no luck. Official datasheet didn't have any info regarding > possible hw bugs too. Thus I had no choice but to find a fix of the > problem myself. > > It took me some time to figure out why the events weren't reported after > the very first link setup (turned out only a full HW reset clears the > PC1R.10 bit state). I thought it could have been connected with some > sleep/idle/power-safe mode. So I disabled the EEE initialization in the > STMMAC driver. It worked. Then I left the EEE mode enabled, but called the > phy_init_eee(phy, 0) method with "clk_stop_enable==0", so PHY wouldn't > stop RXC in LPI mode. And it wonderfully worked. Then I started to dig in > from another side. I left "RXC disable in LPI" mode enabled and tried to > figure out what was going on with the PHY when it stopped reporting events > just by reading from its CSR using phytool utility. It was curious to > discover that any attempt to read from any PHY register caused the problem > disappearance (LED2 started blinking, events got to be reported). Since I > did nothing but a mere reading from a random even EEE-unrelated register I > inferred that the problem must be in some HW/PHY bug. That's how I've got > to the patch introduced here. If you have any better idea what could be a > reason of that weird behavior I'd be glad to test it out on my device. It is a reasonable explanation, and a read should not do any harm. Reviewed-by: Andrew Lunn Andrew _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel