From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 0B33D22D7B6 for ; Tue, 10 Feb 2026 14:32:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770733923; cv=none; b=VT+JVQ8DBHu+cG8FRL8eFqUyTtLIuDnNenAlV9t9N2nYJFOrRpuC0pLDuHQx+mYtGSX52jnrffAujxXFBLg5Sz1HConbJI/1QI4y+hTHVIPher0dDgwOOrw9fV841GSBYAvHukogNOOy6RXhGuGzK0VYokmCZhBlf/Hj7Sdi66o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770733923; c=relaxed/simple; bh=ohaP3f+gViFDezM3994yui/Gxiyd8URY9/WYP1iyMS4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=e8tVlvfHro2aW6sre+3wGCD9Mp8EPf/nkPIqf7f8AyuNyOXvIV1UJu/111F5rRq9fxS0r6b+C7FyG1LZwO6JRZsgVZ3vuyXyqjRv2buvD5cbQv/RrWfCIy8KW+j7zbb3GvNZHdWqzJHlrnNoa0eLSJ1lUz+zrJKF/ZLHljtPKhw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=LJyeDzAt; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="LJyeDzAt" Received: from killaraus.ideasonboard.com (2001-14ba-703d-e500--2a1.rev.dnainternet.fi [IPv6:2001:14ba:703d:e500::2a1]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 9DE41E47; Tue, 10 Feb 2026 15:31:12 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1770733872; bh=ohaP3f+gViFDezM3994yui/Gxiyd8URY9/WYP1iyMS4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LJyeDzAt0bLbhVjCL4vTlxiUHIIOka4k7W80G+K1eI/qEJnnw7IZsvmRkLS0IZ5eu /P8P1k3ciHGtjc2cvrrwRYzYsLptM/BHmO+U0t/nt8mLaHFwUpw4QIFjfZAOIxdget ihtxzCPs/wRtvB5QYVaBc+j8pypFa1LYi79R+674= Date: Tue, 10 Feb 2026 16:31:57 +0200 From: Laurent Pinchart To: "Russell King (Oracle)" Cc: netdev@vger.kernel.org, imx@lists.linux.dev, Andrew Lunn , Clark Wang , "David S. Miller" , Eric Dumazet , Fabio Estevam , Fabio Estevam , Francesco Dolcini , Frank Li , Heiko Schocher , Jakub Kicinski , Joy Zou , Kieran Bingham , Marco Felsch , Martyn Welch , Mathieu Othacehe , Paolo Abeni , Pengutronix Kernel Team , Richard Hu , Sascha Hauer , Shawn Guo , Shenwei Wang , Stefan Klug , Stefano Radaelli , Wei Fang , Xiaoliang Yang , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v2] net: stmmac: imx: Disable EEE Message-ID: <20260210143157.GM2405149@killaraus.ideasonboard.com> References: <20260209202155.2388099-1-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=utf-8 Content-Disposition: inline In-Reply-To: On Tue, Feb 10, 2026 at 12:26:12PM +0000, Russell King (Oracle) wrote: > On Mon, Feb 09, 2026 at 10:21:55PM +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 > > --- > > This patch depends on https://lore.kernel.org/all/E1vNUjC-0000000FhjR-0h6P@rmk-PC.armlinux.org.uk/ > > ... and a few other patches as well. There is also a conflicting change > in net-next: > > commit dc6597fab3e3d291da9e0b4c6f7da01a5a863e80 > Author: Stefan Eichenberger > Date: Tue Jan 20 21:30:04 2026 +0100 > > net: stmmac: dwmac-imx: keep preamble before sfd on i.MX8MP > > > base-commit: 05f7e89ab9731565d8a62e3b5d1ec206485eeb0b > > This is v6.19 > > > prerequisite-patch-id: 9229185bf29c206923075a0450e763664af050bb > > prerequisite-patch-id: e17c3f8a7cb2b18fc0c3c6250773a9680bdabdba > > prerequisite-patch-id: a3c3f8b08fd66ee3ccce632aad3f4a3c21c92718 > > I have no idea what these are. These don't exist in Linus', net, nor > net-next trees. I'm not sure what generates these, but they are useless > unless they also indicate the summary line for the commit in question, > so that one can have some clue what change they're referring to. The first two are mistakes, I had two unrelated DT changes at the base of my branch that I needed for testing, and I forgot to rebase before running git-format-patch. They can be ignored. The last one is your patch (https://lore.kernel.org/all/E1vNUjC-0000000FhjR-0h6P@rmk-PC.armlinux.org.uk/). Note that the value is the patch-id, not the commit ID. > While this is a fix, I think you previously suggested that this isn't > a regression, which suggests it should be merged in net-next (currently > closed due to the merge window) rather than net. I think I was first notified of the issue more than a year ago, so I would indeed not count it as a regression. net-next is fine with me. > Also, referring to another patch doesn't get it applied - netdev > workflow uses patchwork, and patches to be applied need to be there. > If patches depend on each other, they need to be submitted as a > series. So either I need to pick up your patch and send it along > with mine, or you need to pick up my patch and send it with yours. > We need to come to agreement on who is submitting it. I'm happy to submit a series with both, rebased on top of net-next to handle the conflict you pointed out. Is that fine with you ? -- Regards, Laurent Pinchart