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 X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43214C46499 for ; Fri, 5 Jul 2019 10:23:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 190352133F for ; Fri, 5 Jul 2019 10:23:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562322216; bh=8z8MgYp+ZL1IiyyVmtNDGTbfeqiXDaPi/kWvI/Gs86M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=dF1zdpGxwTghDDjfcdAPfrEoN2hYV9LfdfpmZN6t9MqGCw28LVrvITWeIByPV+R6t az7a8ld4T1k3KWGci/i6xz1s1OA01NFa5f9EFPd631u6P9bSTLlbnpGOruxJQotUjE pNm3FtHGPOkM96dPJ3KFQMA8S4Hz2ahbw/BLdvhc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727266AbfGEKXf (ORCPT ); Fri, 5 Jul 2019 06:23:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:56570 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726005AbfGEKXf (ORCPT ); Fri, 5 Jul 2019 06:23:35 -0400 Received: from localhost (83-84-126-242.cable.dynamic.v4.ziggo.nl [83.84.126.242]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 42E6D20989; Fri, 5 Jul 2019 10:23:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562322213; bh=8z8MgYp+ZL1IiyyVmtNDGTbfeqiXDaPi/kWvI/Gs86M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Cdr3lJQVeXTFwh1wrzbUuPQt3cFsua/5z2RznY4fMRjj9iZJDNq9SgJe1AvjZEN4A MPVsJjbl5UKS4YZC7ZUfiWB6622jXHeGCWzDf4a7h8bOm8VXvSMQ49wePwovHcBH40 s4qelC3rn8b/hVjWJ5kPSNN+RAU95XrZISWCgij0= Date: Fri, 5 Jul 2019 12:23:30 +0200 From: Greg Kroah-Hartman To: Lorenzo Pieralisi Cc: Jon Hunter , Vidya Sagar , bhelgaas@google.com, treding@nvidia.com, swarren@nvidia.com, linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org, kthota@nvidia.com, mmaddireddy@nvidia.com, sagar.tv@gmail.com Subject: Re: [PATCH V3] PCI: tegra: Enable Relaxed Ordering only for Tegra20 & Tegra30 Message-ID: <20190705102330.GA11541@kroah.com> References: <20190704150428.4035-1-vidyas@nvidia.com> <20190704160948.GA28058@e121166-lin.cambridge.arm.com> <310ce6f7-9379-9857-ac7c-53118b80966b@nvidia.com> <20190705093859.GA17491@e121166-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190705093859.GA17491@e121166-lin.cambridge.arm.com> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Fri, Jul 05, 2019 at 10:38:59AM +0100, Lorenzo Pieralisi wrote: > [+Greg] > > On Fri, Jul 05, 2019 at 09:57:25AM +0100, Jon Hunter wrote: > > Hi Lorenzo, > > > > On 04/07/2019 17:09, Lorenzo Pieralisi wrote: > > > On Thu, Jul 04, 2019 at 08:34:28PM +0530, Vidya Sagar wrote: > > >> Currently Relaxed Ordering bit in the configuration space is enabled for > > >> all PCIe devices as the quirk uses PCI_ANY_ID for both Vendor-ID and > > >> Device-ID, but, as per the Technical Reference Manual of Tegra20 which is > > >> available at https://developer.nvidia.com/embedded/downloads#?search=tegra%202 > > >> in Sec 34.1, it is mentioned that Relexed Ordering bit needs to be enabled in > > >> its root ports to avoid deadlock in hardware. The same is applicable for > > >> Tegra30 as well though it is not explicitly mentioned in Tegra30 TRM document, > > >> but the same must not be extended to root ports of other Tegra SoCs or > > >> other hosts as the same issue doesn't exist there. > > >> > > >> Signed-off-by: Vidya Sagar > > > > > > You forgot Thierry's ACK, I added it back but next time pay more > > > attention please. > > > > > > You should link the versions through eg git send-email > > > --in-reply-to=Message-Id so that it is easier to follow. > > > > > >> --- > > >> V3: > > >> * Modified commit message to make it more precise and explicit > > >> > > >> V2: > > >> * Modified commit message to include reference to Tegra20 TRM document. > > >> > > >> drivers/pci/controller/pci-tegra.c | 7 +++++-- > > >> 1 file changed, 5 insertions(+), 2 deletions(-) > > > > > > I applied it to pci/tegra after rewriting the whole commit log and > > > adding a Fixes: tag that you or someone at Nvidia will follow up; > > > I will check. > > > > I had a chat with Vidya last night to understand the issue, so now I > > have a good understanding of the problem this has caused, which is very > > unfortunate indeed! > > > > Vidya mentioned that you would like us to get this backported to stable > > branches. Please correct me if I am wrong here. We can certainly do > > that, but I do have concerns about doing so, for non-Tegra devices > > inparticularly, given that this has been around for sometime now. Hence, > > I was wondering if we should leave this soak in the mainline for at > > least a kernel release cycle before doing so. I really don't want to > > break stable for anyone. What are your thoughts on this? > > I looped in Greg to pick his brain, since it is unclear how we should > apply the stable kernel rules on this specific patch. Basically, this > technically is not a bug, it is just bad code that forces a feature on > ALL kernels that compile the PCI Tegra Controller driver in the kernel. > I would really really want to have this patch applied to all stable > kernels but first as you said it is better to apply it to mainline and > check it does not cause any issues on any other arch/platform then > we can think about backporting it to stable kernels. You all have read the stable kernel rules, right: https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html Patches have to be upstream first. After it is merged in Linus's tree, post the patches with the git commit ids to stable@vger and we will be glad to review them there. thanks, greg k-h