From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 9E59D134B3 for ; Thu, 9 Nov 2023 09:46:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="BWdti6VB" 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 7AC0A2D49; Thu, 9 Nov 2023 01:46:38 -0800 (PST) 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=cToWrjKVkKlNsoeH6fQytqUtrMdfuAVIxZoekhMSeHU=; b=BWdti6VBodHQYvNyN5+fj7ApxK pBBN4JBp6GoSQOmrIrCZt585hkq3fgNoHm14umxjNweakNB0fuBEo454E4n3j0Dv9wNleEfP1cpHu Y2lNsjV01IZVD29zbeJb5X4bN7AzfiywYP/PMR43P0K4NX2laKuksRwSdTZtuvWApcX7VSCv9ksf0 S7VuzWrJHFWVPqXqPR92IJ6o7iTORGUFBU3iknfCD28oRjjIowdXCO8tApMtnTHDdG0Xa6p3PQsiB da+LDhPjglZxooSqrfPmr6R/deiZ/gHxOkFNVWe3prUuISHU7Ji2b4p1nwfMWOr+WI6uRmu8wmQMz EMwySoHQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:35116) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1r11cD-0002DX-0q; Thu, 09 Nov 2023 09:46:21 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1r11cB-0000Rt-RJ; Thu, 09 Nov 2023 09:46:19 +0000 Date: Thu, 9 Nov 2023 09:46:19 +0000 From: "Russell King (Oracle)" To: Gan Yi Fang Cc: Alexandre Torgue , Jose Abreu , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Maxime Coquelin , Joakim Zhang , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Looi Hong Aun , Voon Weifeng , Song Yoong Siang Subject: Re: [PATCH net 1/1] net: stmmac: fix MAC and phylink mismatch issue after resume with STMMAC_FLAG_USE_PHY_WOL enabled Message-ID: References: <20231109050027.2545000-1-yi.fang.gan@intel.com> 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-Disposition: inline In-Reply-To: Sender: Russell King (Oracle) On Thu, Nov 09, 2023 at 09:15:36AM +0000, Russell King (Oracle) wrote: > On Thu, Nov 09, 2023 at 01:00:27PM +0800, Gan Yi Fang wrote: > > From: "Gan, Yi Fang" > > > > The issue happened when flag STMMAC_FLAG_USE_PHY_WOL is enabled. > > It can be reproduced with steps below: > > 1. Advertise only one speed on the host > > 2. Enable the WoL on the host > > 3. Suspend the host > > 4. Wake up the host > > > > When the WoL is disabled, both the PHY and MAC will suspend and wake up > > with everything configured well. When WoL is enabled, the PHY needs to be > > stay awake to receive the signal from remote client but MAC will enter > > suspend mode. > > > > When the MAC resumes from suspend, phylink_resume() will call > > phylink_start() to start the phylink instance which will trigger the > > phylink machine to invoke the mac_link_up callback function. The > > stmmac_mac_link_up() will configure the MAC_CTRL_REG based on the current > > link state. Then the stmmac_hw_setup() will be called to configure the MAC. > > > > This sequence might cause mismatch of the link state between MAC and > > phylink. This patch moves the phylink_resume() after stmamc_hw_setup() to > > ensure the MAC is initialized before phylink is being configured. > > Isn't this going to cause problems? > > stmamc_hw_setup() calls stmmac_init_dma_engine(), which then calls > stmmac_reset() - and stmmac_reset() can fail if the PHY clock isn't > running, which is why phylink_resume() gets called before this. I think these two commits should be reviewed to understand why the code is the way it is, and why changing it may cause regressions: 90702dcd19c0 ("net: stmmac: fix MAC not working when system resume back with WoL active") 36d18b5664ef ("net: stmmac: start phylink instance before stmmac_hw_setup()") As part of my work on stmmac that got junked, I was looking at a solution to the "we need the PHY clock to be running for the MAC to work for things like reset" problem - but those patches got thrown away when stmmac folk were very nitpicky over %u vs %d in format strings to print what was a _signed_ value that stmmac code stupidly converts to an unsigned integer... it's still a signed integer no matter if code decides to use "unsigned int". I suspect all those patches (and there was a considerable number of them) have now been expired from git, so are now totally lost, and honestly I have no desire to put further work into stmmac stuff. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!