From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (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 609CC3242B7; Wed, 21 Jan 2026 17:33:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769016825; cv=none; b=ZdDloTOr+wHAcn1/zBVPKDqGX0PP9pTT7rFUP5vrh8tWVYMUjSUmIQYCwIUtODSmpXGyqUrbFQ6YnDRVTbedR/YeG+k/EQuXsjlgLF0lax93IOdm1ToAr5Uc/r2utuVOEfgtvhrBO66VDUSXPk537JoZLHGal8N0sRmRClLnpf4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769016825; c=relaxed/simple; bh=xrjO5eOuxQk0o5/bDxwPgb4Y7hn7eIm9ywDo98NmTJA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mmc++zE1i+m4XK308XCkcn6eVdL2RIQi5ixhXvfkDpj4z8UG8wD1XXqRQ/uiMkSlL0kpyJQhCnhYq7MOJOOtZUM2RFMBaWQZyhBENS4RUF+kuhZpfeotCwuijfMeTxDSYJcY7f5puFAUSrfOVEIl9P0dcj/kXmw9RbS+mf6QUlY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=RGQRrLaf; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="RGQRrLaf" 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=ZwVQ7DVnwRsf/W7oc0aqwTt7dOJIeDibahFoGDhgMVo=; b=RGQRrLafnzAKAK9bhLuJbuYq9m cw3YwU4Mmw1YcwJGdmmV+AKinp/sIzQLOusOyBiHud9uW0hCPFU6pAOzdGvp1BVxiYu/1xJMH7YdE S8PvtpPsGXrcBdF0rlGWVEGhe9m5ZuuMRGLK4rsc5sPx293nNUjtUbL1xrS4Mriibo39YoAh/wqib smF510gFCIRAzz4sGVGA2CvR6zMmrUxzvFcHqjqh1Z5ZtHoZdlhdnJdEM9HW1e++AIWMtv4JRf12s nPb3esoJDFqohvi7oFuZ3NH2gCyFtR711mxtWFOA88fY8/wLU9ip+P5piOsKU1S/VFHHvuvMDoI2p rTa3Rd9A==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:40482) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1vic5E-000000007oR-1qPB; Wed, 21 Jan 2026 17:33:32 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1vic5A-000000000Bp-1guX; Wed, 21 Jan 2026 17:33:28 +0000 Date: Wed, 21 Jan 2026 17:33:28 +0000 From: "Russell King (Oracle)" To: Vladimir Oltean Cc: Jakub Kicinski , linux-phy@lists.infradead.org, davem@davemloft.net, maxime.chevallier@bootlin.com, alexandre.torgue@foss.st.com, mohd.anwar@oss.qualcomm.com, neil.armstrong@linaro.org, hkallweit1@gmail.com, mcoquelin.stm32@gmail.com, netdev@vger.kernel.org, edumazet@google.com, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, vkoul@kernel.org, andrew@lunn.ch, pabeni@redhat.com, andrew+netdev@lunn.ch, linux-stm32@st-md-mailman.stormreply.com Subject: Re: [net-next,05/14] net: stmmac: add stmmac core serdes support Message-ID: References: <20260119192125.1245102-1-kuba@kernel.org> <20260120081844.7e6aq2urhxrylywi@skbuf> <20260120121114.2aedgu42i2wax3yp@skbuf> <20260121162345.4jpzvwqhfqxd7tl7@skbuf> 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: <20260121162345.4jpzvwqhfqxd7tl7@skbuf> Sender: Russell King (Oracle) On Wed, Jan 21, 2026 at 06:23:45PM +0200, Vladimir Oltean wrote: > On Wed, Jan 21, 2026 at 02:46:42PM +0000, Russell King (Oracle) wrote: > > On Tue, Jan 20, 2026 at 02:11:14PM +0200, Vladimir Oltean wrote: > > > On Tue, Jan 20, 2026 at 10:12:46AM +0000, Russell King (Oracle) wrote: > > > > First, I'll say I'm on a very short fuse today; no dinner last night, > > > > at the hospital up until 5:30am, and a fucking cold caller rang the door > > > > bell at 10am this morning. Just fucking our luck. > > > > > > Sorry to hear that. > > > > > > > On Tue, Jan 20, 2026 at 10:18:44AM +0200, Vladimir Oltean wrote: > > > > > Isn't it sufficient to set pl->pcs to NULL when pcs_enable() fails and > > > > > after calling pcs_disable(), though? > > > > > > > > No. We've already called mac_prepare(), pcs_pre_config(), > > > > pcs_post_config() by this time, we're past the point of being able to > > > > unwind. > > > > > > I'm set out to resolve a much smaller problem. > > > > > > Calling it a full "unwind" is perhaps a bit much, because pcs_pre_config() > > > and pcs_post_config() don't have unwinding equivalents, unlike how > > > pcs_enable() has pcs_disable(). I don't see what API convention would be > > > violated if phylink decided to drop a PCS whose enable() returned an error. > > > > While pcs_pre_config() and pcs_post_config() do not have unwinding > > equivalents (what would they be?) the issue here is that these could > > have changed any state that isn't simply undone by calling > > pcs_disable(). > > > > For example, pcs_pre_config() could have reprogrammed signal routing, > > clocking, or power supplies to blocks. > > > > This already applies to Marvell DSA pcs-639x.c, where the pre/post > > config hooks change the power state of the PCS block (for errata > > handling), and the only way that gets undone is via a call to > > pcs_disable() which explicitly disables IRQs and power for the PCS. Its > > pcs_disable() isn't a strict reversal of pcs_enable(), it does more. > > > > We already declare the interface to be dead on pcs_post_config() > > failure, but we don't do that for pcs_enable() failure. > > > > Maybe I need to explicitly state that pcs_disable() does not directly > > balance pcs_enable(), but that _and_ the effects of pcs_pre_config() > > and pcs_post_config(). However, that itself will add to the problems. > > What if pcs_pre_config() and pcs_post_config() succeed but not > > pcs_enable()? pcs-639x needs pcs_disable() to be called, but if we > > require pcs_disable() to be balanced with a successful call to > > pcs_enable(), that messes up that driver, and pretty much makes it > > impossible to work around the errata. > > What if we reordered phylink_major_config() such that phylink_pcs_enable() > comes first, followed by phylink_pcs_pre_config() -> phylink_mac_config() -> > phylink_pcs_post_config()? Superficially looking at pcs-639x, I don't > think it would break. I'm sorry, but I don't have time to continue this discussion today. I woke late, we're trying to cram in the meals (in the middle of delayed lunch-time dinner right now), work wants a quick call to discuss a project that I missed the meeting for yesterday (which I haven't yet had time for...) Sorry, but while you may wish to get this sorted, for me this is a very low priority issue that can be addressed later. Don't think I will have time to review anything you send - and that's not a personal attack, it's because I'm barely managing to hold everything together at my end, and I don't have the time. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!