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 2D9892F9D82 for ; Tue, 10 Feb 2026 16:33:14 +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=1770741195; cv=none; b=A3BAoQln56vMvMQH0yvMtFiePQ1X7atw7tqK0c+7mHS02moYcjiMyAnDdU8v9A4XwuF8/vKzzGm2bvtFkGX7Lu/hwATgBhfieKREW5KNeNvn4GGZQCW1oL9Ew2ZVnXtuXiQ8UUzIsehG8m0iHRywa3jVKYCIE4j5wLHYF9Iq2sk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770741195; c=relaxed/simple; bh=i1aVOG6FuUTeV/Uu8fht8rO+RzylUal3rs8C5UoVrEg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ODRj1VsPi3+K70JaXXoBGFwcWzZLicoBCqM4JkSmPEUGDEM8N58uQIf32tvSlBty/ibM1ZDxHwOk2mVxWy4TYg//zonucnSqTaOKu1pYwfVBs8pqzU3PONoehendJDcLuMt+nWqMOkd5D7WvIQnVfTH9pfSkz9TvbirY/M6nh8w= 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=AXZNE2zi; 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="AXZNE2zi" 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 D21A9838; Tue, 10 Feb 2026 17:32:24 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1770741145; bh=i1aVOG6FuUTeV/Uu8fht8rO+RzylUal3rs8C5UoVrEg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AXZNE2ziNn68zOIeNK85ipouJXapazVjN22FGhr85f6i+2RujMwXW7Q4+FP6kd/vz z2PWGpliO5H4wqjEH7Xnolekkx/s9QYOFxGgoLPFoRcVkWWVJGgUxObqXdXgtGjrnP 9kPBqTYqJ7peMDQ3kL+w8tqCSJEgFUMcfYU4ve9c= Date: Tue, 10 Feb 2026 18:33:10 +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: <20260210163310.GO2405149@killaraus.ideasonboard.com> References: <20260209202155.2388099-1-laurent.pinchart@ideasonboard.com> <20260210143157.GM2405149@killaraus.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: <20260210143157.GM2405149@killaraus.ideasonboard.com> On Tue, Feb 10, 2026 at 04:31:59PM +0200, Laurent Pinchart wrote: > 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 ? If you would like me to submit a series with both patches, should I resolve the conflict with "net: stmmac: dwmac-imx: keep preamble before sfd on i.MX8MP" by inserting the STMMAC_FLAG_EEE_DISABLE flag as BIT(10) and change the value of subsequent flags as you did, or add it at the end (BIT(15)) ? I'm also happy if you take my patch and submit a series with both. -- Regards, Laurent Pinchart