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 000EF36DA10 for ; Mon, 23 Mar 2026 09:55:39 +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=1774259742; cv=none; b=ja5slrqIVOg8p1qRyqMFhbsIAbduMbexHKWyHUKayj4LIVeCNwee7z+di+ngKXIDM0QT/BwLpPDMrsBLcx+tkTQKeDK2+qD85vz5KK0ada7IFx+Af49zMnpLv7Vxzu/K2W2goG2qetW3vqIPcqQdQW7Md+z60W2ziWwhSNJW/MY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774259742; c=relaxed/simple; bh=GSqj15XOYgZ+z3rGtlQoS2JdFGH8XW37H8ENXEVYxQ8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Q+wbc9NWSBflJaZ0pZmM3pLUOnmrXh3iuPHjtjdbh/wokxnNKgMlY9He7Ql8WTtwaN7bn2JLVmeNIy7ZgKGUlKZapE/WgkosiCNfpbsCGgKpKxuOojlHIFcA9HeWIxBcVu29f3fokZ0H/t/8bmUdaBkFZxypvSORQHaI1WJBsCU= 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=KSobhkUH; 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="KSobhkUH" 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=lrsfFTGfYyLKxF07ePPhHcfSutGOTt7NkUKvGum/24k=; b=KSobhkUH1DcN4nToJvqyD5yAUQ /YpHvXdbSzU/y6TgMZ2xtyfj7RPYzfRRFYJvfvJV8J5aiOWZgDg8+Otj13FDeCHV8cyXcj6+gVISn Gp4j/vwmO0HAIkQSvho4ojB8Cgnow6dWrQ8onHswqgD55iniIYO9q8WKP/M6Pywi3EkY5I4Zv2Zlc Ua/Yy8CL4gLXFmaIx4CdSXbes8YbsXVCJiC+jHf4ODYwLNia5zNHTJrLJobSaLhf1VGO+gw3NHXJU BrNyURQGWUCtEdKSVuVDuWRkDoObJqSlntuD5RJHQOZuDT6VsZjm1Fu0tj4lLxOAuljroKiHj9FE6 tHgTrPqA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:57086) 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 1w4c0X-000000000GI-2nAx; Mon, 23 Mar 2026 09:55:37 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1w4c0W-000000003w9-0ocX; Mon, 23 Mar 2026 09:55:36 +0000 Date: Mon, 23 Mar 2026 09:55:36 +0000 From: "Russell King (Oracle)" To: Laurent Pinchart Cc: netdev@vger.kernel.org, imx@lists.linux.dev, Andrew Lunn , "David S. Miller" , Eric Dumazet , Fabio Estevam , Francesco Dolcini , Frank Li , Jakub Kicinski , Joy Zou , Kieran Bingham , Marco Felsch , Paolo Abeni , Pengutronix Kernel Team , Stefan Klug , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v3 1/2] net: stmmac: provide flag to disable EEE Message-ID: References: <20260323093933.1785583-1-laurent.pinchart@ideasonboard.com> <20260323093933.1785583-2-laurent.pinchart@ideasonboard.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: <20260323093933.1785583-2-laurent.pinchart@ideasonboard.com> Sender: Russell King (Oracle) On Mon, Mar 23, 2026 at 11:39:32AM +0200, Laurent Pinchart wrote: > From: "Russell King (Oracle)" > > Some platforms have problems when EEE is enabled, and thus need a way > to disable stmmac EEE support. Add a flag before the other LPI related > flags which tells stmmac to avoid populating the phylink LPI > capabilities, which causes phylink to call phy_disable_eee() for any > PHY that is attached to the affected phylink instance. > > iMX8MP is an example - the lpi_intr_o signal is wired to an OR gate > along with the main dwmac interrupts. Since lpi_intr_o is synchronous > to the receive clock domain, and takes four clock cycles to clear, this > leads to interrupt storms as the interrupt remains asserted for some > time after the LPI control and status register is read. > > This problem becomes worse when the receive clock from the PHY stops > when the receive path enters LPI state - which means that lpi_intr_o > can not deassert until the clock restarts. Since the LPI state of the > receive path depends on the link partner, this is out of our control. > We could disable RX clock stop at the PHY, but that doesn't get around > the slow-to-deassert lpi_intr_o mentioned in the above paragraph. > > Previously, iMX8MP worked around this by disabling gigabit EEE, but > this is insufficient - the problem is also visible at 100M speeds, > where the receive clock is slower. > > There is extensive discussion and investigation in the thread linked > below, the result of which is summarised in this commit message. > > Reported-by: Laurent Pinchart > Closes: https://lore.kernel.org/r/20251026122905.29028-1-laurent.pinchart@ideasonboard.com > Signed-off-by: Russell King (Oracle) As you are sending this on my behalf, you need to add your s-o-b after mine: Any further SoBs (Signed-off-by:'s) following the author's SoB are from people handling and transporting the patch, but were not involved in its development. SoB chains should reflect the **real** route a patch took as it was propagated to the maintainers and ultimately to Linus, with the first SoB entry signalling primary authorship of a single author. Thanks. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!