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 4BB323932CA for ; Mon, 13 Apr 2026 07:28:53 +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=1776065334; cv=none; b=OayT3vdyz+vzY9ebwZceRlIAH3MOPOyfN1kP2Ae60NSppJ8WN0W3QJuOs6wA39U1UDuyOocfcBFzxncJTCoHWTxAVaDRdRmdU3WmONZv+snQSIRbFPfOz9YpDKT5IFKxfdHl3+WoM0hyEMCAxcyEQPEyQM1mr84EDHjyLv9RBDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776065334; c=relaxed/simple; bh=b+REnLyFlt8gAAHb0UfigkbwOTdNQ/EP71OIdJOdRZs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=E3gFvQ3LPokclZHqiAvDCpODlkqzpXZ/a6VTOXPTxrvj+0QbpzCBppQBECX9chwQ1oLT2z/6Y3HLCoUCGsGPvgyOIohhd2Ptp53YEzLItENANiCBnn/LuotqgxUrpG24++rCyXsGtBCwAKdGdCwclLLb/sTKNr1JRsI5fJOJm7M= 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=vGVrmcFP; 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="vGVrmcFP" 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-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To: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=vBAkUVC0LMguyggH1Fj4JtxZi9KWJ36XVZrJatk2ddU=; b=vGVrmcFPQ6S49Z9B7XUiJ2/XJx TCePPJ2Ig0JP/H6FFr0MQ4Icbi5GdYptvkxEcqqALfQeLVdCu4ZXrmo81ZP75Pa/c8jnMjIbTOMOo fFuRQyBW0FruqRiC4GKGfZh3sw13Dfp51fGH2wi8gewQXzrEVxWTmVT9xCmdVeRkcaG4y4LwwInqB umUXdX8MsLxLHlkf8/YsQiT+lqJ0H7GgARReY0yz3qUPLWvXfKPpHUnWS3THK0j5dvSoAhgknRDjU lfwY0Mssi9nMN9WvYBY7p5D0+hyn5iEuoKj2WyOFPYNOOiLJJNYFvVxiAabutE3z3WDzKWIu9Ef2R JqTNF7Dw==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:37492) 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 1wCBix-000000007wY-3NJR; Mon, 13 Apr 2026 08:28:47 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.98.2) (envelope-from ) id 1wCBiw-000000008Rt-2JjB; Mon, 13 Apr 2026 08:28:46 +0100 Date: Mon, 13 Apr 2026 08:28:46 +0100 From: "Russell King (Oracle)" To: Sam Edwards Cc: Maxime Chevallier , Andrew Lunn , Alexandre Torgue , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , linux-arm-kernel@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com, netdev@vger.kernel.org, Paolo Abeni Subject: Re: [PATCH net-next] net: stmmac: enable RPS and RBU interrupts Message-ID: References: <266998d8-7e38-4bae-a4df-2f889538fe88@bootlin.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 Content-Transfer-Encoding: 8bit In-Reply-To: Sender: Russell King (Oracle) On Mon, Apr 13, 2026 at 08:24:59AM +0100, Russell King (Oracle) wrote: > On Sun, Apr 12, 2026 at 06:42:04PM -0700, Sam Edwards wrote: > > On Sun, Apr 12, 2026 at 7:23 AM Russell King (Oracle) > > wrote: > > > As the dwmac 5.0 core receive path seems to lock up after the first > > > RBU, I never see more than one of those at a time. > > > > > > Right now, I consider this pretty much unsolvable - I've spent quite > > > some time looking at it and trying various approaches, nothing seems > > > to fix it. However, adding dma_rmb() in the descriptor cleanup/refill > > > paths does seem to improve the situation a little with the 480Mbps > > > case, because I think it means that we're reading the descriptors in > > > a more timely manner after the hardware has updated them. > > > > Hey Russell, > > > > I'd like to repro this but I currently can't boot net-next. My issue > > is the same as [1], and the patch to fix it [2] isn't yet committed > > anywhere apparently. > > > > This prevents my Jetson Xavier NX from starting at all (and after > > enough attempts, corrupts eMMC); I'm surprised you're not suffering > > the same effects. But because this bug lives in the IOMMU subsystem > > (and it has somewhat inconsistent effects), perhaps this is just a > > different way it manifests? Could you confirm whether your dwmac hang > > happens with IOMMU disabled, and/or with [1] reverted or [2] applied? > > > > I'm using a defconfig build and a fairly minimal cmdline (just > > console=, root=, and rootwait). > > > > Cheers, > > Sam > > > > [1] https://lore.kernel.org/all/8800a38b-8515-4bbe-af15-0dae81274bf7@nvidia.com/ > > [2] https://lore.kernel.org/all/0-v1-664d3acaabb9+78b-iommu_gather_always_jgg@nvidia.com/ > > In the second link, there is this sub-thread: > > https://lore.kernel.org/all/ee2c2044-e329-4cdd-ac35-9365824d3677@arm.com/ > > which was committed into -rc as: > > 7e0548525abd iommu: Ensure .iotlb_sync is called correctly > > which does fix IOMMU problems which caused net-next which reports itself > as v7.0-rc6 failing to boot with ext4 errors. See: > > https://lore.kernel.org/r/adZTGOjjJrVJOcT8@shell.armlinux.org.uk > > which resulted in it being merged into v7.0-rc7 just before Thursday's > net tree merge. Due to the way net-next is operated, that means that > net-next on Thursday evening gained this fix. > > Involving Linus in the problem meant he was aware of it, and explaining > how netdev works allowed him to delay the merging of the net tree to > ensure net-next gained the fix. I'll also state what I've stated previously about the iperf3 problem: it seems to go back a long time, certainly before I started cleaning up the stmmac driver which is now well over a year ago. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!