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 4B3C7EC01B9 for ; Mon, 23 Mar 2026 10:08:11 +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=mb0AvQgjgSknt3B21ENaWWdGHU3LKRYBpvSFRD1KkSQ=; b=csIlIZYMU09ZDBhqSSj44h2GfT DmX7NsckKoXxjENs1huTOXU6+huPnlURZNh+QvFUJBU2JzvlW/A6T5s+WqN3Rdiz7fcbWn0kQmn0C E1SuYi7vOhWIPcUhAFZZnDWxzg2ZfanUIegJmW4md/xxCqEmDH3vRCZy5pnpzmQ452+bkWFOtQfzt BcwEIaBjccwkTyfIxPbqiTGrAhYQhY9enKdsp7ph03V72nAbZTcgQGFPdBQAAMKP+Uo2DCROqw4mW YbfYPh/7Tnaol0b+JMWRdaMywA/llpdkwkmqlb7H7f37WQAyj/sBGU2y2F3U2XglD8JSRhlSBwjdl Ts6NHiQg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w4cCc-0000000GSnB-1JFM; Mon, 23 Mar 2026 10:08:06 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w4cCa-0000000GSmo-2S8c for linux-arm-kernel@lists.infradead.org; Mon, 23 Mar 2026 10:08:05 +0000 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 747CB225; Mon, 23 Mar 2026 11:06:46 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1774260406; bh=iyWyNlV51BpyMkw7V5QwsB1bepmvYO6pQ+kULfmgUXg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rP0iqGlGqtP8yALjUej6Mzd+BVB60eXEQ+JfZWcKub/mOgG7qPq0t7htAkmAuKR6l pcPJxxSC8Y5eQh/zVpgf/X7zpucSMTQI379kjsX0oeUNsCOzHOeJ9jljDg7tBi10xy +bu9gvl5k6jlX9RfCE+CNiEW8lIPsvHWggzblZqQ= Date: Mon, 23 Mar 2026 12:08:01 +0200 From: Laurent Pinchart To: "Russell King (Oracle)" 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: <20260323100801.GA1514659@killaraus.ideasonboard.com> References: <20260323093933.1785583-1-laurent.pinchart@ideasonboard.com> <20260323093933.1785583-2-laurent.pinchart@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260323_030804_767370_F634C1B6 X-CRM114-Status: GOOD ( 27.48 ) 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 09:55:36AM +0000, Russell King (Oracle) wrote: > 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: Oops, I'm not sure how I missed that. Sorry. Signed-off-by: Laurent Pinchart > 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. -- Regards, Laurent Pinchart