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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 08234EC01B1 for ; Mon, 23 Mar 2026 09:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id: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-Owner; bh=c1JtUgAJo9zz29RauK3FUJzPu0iLBjOxgL8d3JFQYgo=; b=XNQsQPZybruZUMfg7KhlnohhP2 JS7K0VPjZcGz/UIX3xHwf8YBW9CEuVjB5bIqoAnBCRhbCjNABH24HalwSO22coI/TehCrUdaVL3Kt 2RWBARF5zwiApsdNteBS+S+RQCUBusdv8tRFSwfCmvx+nuHtGWUQl3Ettl4F7poRmbQDvts2W+Tlr 8KbNjnKSUf/gGxZ2TZhy8Iix/FadZBkArYV3oj/fE9DAxi8M3bHE9DouoIgSpL1c5vobvhthq9t5j wrEziHaYaoqX+UfrOQQ5+w8Od+eK1t/nZLse52690Lm/9VgqTT2Zc8UuzCi9UVx8QXBL2iOjLvi9o dbbrbpIg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w4bzA-0000000GQ63-2trO; Mon, 23 Mar 2026 09:54:12 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w4bz8-0000000GQ5h-0DZF for linux-arm-kernel@lists.infradead.org; Mon, 23 Mar 2026 09:54:11 +0000 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=c1JtUgAJo9zz29RauK3FUJzPu0iLBjOxgL8d3JFQYgo=; b=Cxjo/Yn0PNrXJyYp78jYI1Lr3m ju8Kh2IvRY5ar5bE5Pw+4HTNk0GKuL4aEgKkhhVFh2kN/jnHBjSX4/N0WIIugMxhZnKVB4lInlcMG HtAA+hyqdOCA2kruIi0C35/bz3L//QZtb2JepV0Rai8uJZdTNMfgjdxXFh2Dg9IZw1sw91RnaP8Io fgQpwDXpxqpd/ThjJY80fbLgeHm29H4xXzRlziw37OvjpNrM1HCzCUap2NNVuTxrrNHILg8Fc1mnr DXWbtjrtjP1t+jNFZQAC38vH6rYaktnzIfwCcGtI77IgYt7JlonIIYcwy3LWm5V0BKnsFUrIpo3wL c3Z0XMKg==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:54524) 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 1w4byv-000000000Fk-2JZx; Mon, 23 Mar 2026 09:53:57 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1w4byt-000000003w1-0vsp; Mon, 23 Mar 2026 09:53:55 +0000 Date: Mon, 23 Mar 2026 09:53:55 +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 2/2] net: stmmac: imx: Disable EEE Message-ID: References: <20260323093933.1785583-1-laurent.pinchart@ideasonboard.com> <20260323093933.1785583-3-laurent.pinchart@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260323093933.1785583-3-laurent.pinchart@ideasonboard.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260323_025410_093292_54DCA673 X-CRM114-Status: GOOD ( 15.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Mar 23, 2026 at 11:39:33AM +0200, Laurent Pinchart wrote: > The i.MX8MP suffers from an interrupt storm related to the stmmac and > EEE. A long and tedious analysis ([1]) concluded that the SoC wires the > stmmac lpi_intr_o signal to an OR gate along with the main dwmac > interrupts, which causes an interrupt storm for two reasons. > > First, there's a race condition due to the interrupt deassertion being > synchronous to the RX clock domain: > > - When the PHY exits LPI mode, it restarts generating the RX clock > (clk_rx_i input signal to the GMAC). > - The MAC detects exit from LPI, and asserts lpi_intr_o. This triggers > the ENET_EQOS interrupt. > - Before the CPU has time to process the interrupt, the PHY enters LPI > mode again, and stops generating the RX clock. > - The CPU processes the interrupt and reads the GMAC4_LPI_CTRL_STATUS > registers. This does not clear lpi_intr_o as there's no clk_rx_i. > > An attempt was made to fixing the issue by not stopping RX_CLK in Rx LPI > state ([2]). This alleviates the symptoms but doesn't fix the issue. > Since lpi_intr_o takes four RX_CLK cycles to clear, an interrupt storm > can still occur during that window. In 1000T mode this is harder to > notice, but slower receive clocks cause hundreds to thousands of > spurious interrupts. > > Fix the issue by disabling EEE completely on i.MX8MP. > > [1] https://lore.kernel.org/all/20251026122905.29028-1-laurent.pinchart@ideasonboard.com/ > [2] https://lore.kernel.org/all/20251123053518.8478-1-laurent.pinchart@ideasonboard.com/ > > Signed-off-by: Laurent Pinchart Reviewed-by: Russell King (Oracle) Thanks! -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!