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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E656C5479D for ; Wed, 11 Jan 2023 23:10:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235605AbjAKXKi (ORCPT ); Wed, 11 Jan 2023 18:10:38 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235566AbjAKXKh (ORCPT ); Wed, 11 Jan 2023 18:10:37 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D9B232255; Wed, 11 Jan 2023 15:10:36 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B55F861ED6; Wed, 11 Jan 2023 23:10:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E04C6C433EF; Wed, 11 Jan 2023 23:10:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673478635; bh=++uluPFMowPrY8s1xfgmEUXDgen39mn6C1pbnUZ2MU4=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=kBqcCXiYgbOo0fz6xo/YOGVM2XLI/TGaRt6I6q6PjPGZghKE/om05zyqfQApLqDYT jmtXbxl6mYgeTjvYJzO/uS6FXr7Jtgv4Vt9rxojdIH0almjY/NGOnq8M98oF8kwfKv mCwqtmnaMLXuy53tHGIvRSpO6jJpLEDBsKoIBdgEktC94gHq4mrfugdJv1Tl6xx0Op Kf2NLycwahihsEOlR2wzo34lyCEDQAN00QCHEvDa7CZKU+ikaJv0Sg+J3cVXJ9bOw8 YdLlhfDNoHLfjF0ARFO6qKNG2/37bTKDikGli5xn/eqK7HJNGt8MYp2vc2UsdDCZZn X5NH/nGhjaa4A== Date: Wed, 11 Jan 2023 17:10:33 -0600 From: Bjorn Helgaas To: Sathyanarayanan Kuppuswamy Cc: Vidya Sagar , bhelgaas@google.com, ruscur@russell.cc, oohall@gmail.com, treding@nvidia.com, jonathanh@nvidia.com, mmaddireddy@nvidia.com, kthota@nvidia.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, vsethi@nvidia.com, linuxppc-dev@lists.ozlabs.org, sagar.tv@gmail.com Subject: Re: [PATCH V1] PCI/AER: Configure ECRC only AER is native Message-ID: <20230111231033.GA1714672@bhelgaas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Jan 11, 2023 at 01:42:21PM -0800, Sathyanarayanan Kuppuswamy wrote: > On 1/11/23 12:31 PM, Vidya Sagar wrote: > > As the ECRC configuration bits are part of AER registers, configure > > ECRC only if AER is natively owned by the kernel. > > ecrc command line option takes "bios/on/off" as possible options. It > does not clarify whether "on/off" choices can only be used if AER is > owned by OS or it can override the ownership of ECRC configuration > similar to pcie_ports=native option. Maybe that needs to be clarified. Good point, what do you think of an update like this: diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 6cfa6e3996cf..f7b40a439194 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4296,7 +4296,9 @@ specified, e.g., 12@pci:8086:9c22:103c:198f for 4096-byte alignment. ecrc= Enable/disable PCIe ECRC (transaction layer - end-to-end CRC checking). + end-to-end CRC checking). Only effective + if OS has native AER control (either granted by + ACPI _OSC or forced via "pcie_ports=native"). bios: Use BIOS/firmware settings. This is the the default. off: Turn ECRC off I don't know whether the "ecrc=" parameter is really needed. If we were adding it today, I would ask "why not enable ECRC wherever it is supported?" If there are devices where it's broken, we could always add quirks to disable it on a case-by-case basis. But I think the patch below is the right thing to do for now. Vidya, did you trip over an issue because of this, e.g., a conflict between firmware use of AER and Linux use of it? If so, maybe we could mention a symptom on the commit log. But my guess is you probably found this by inspection. Bjorn > > Signed-off-by: Vidya Sagar > > --- > > drivers/pci/pcie/aer.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c > > index e2d8a74f83c3..730b47bdcdef 100644 > > --- a/drivers/pci/pcie/aer.c > > +++ b/drivers/pci/pcie/aer.c > > @@ -184,6 +184,9 @@ static int disable_ecrc_checking(struct pci_dev *dev) > > */ > > void pcie_set_ecrc_checking(struct pci_dev *dev) > > { > > + if (!pcie_aer_is_native(dev)) > > + return; > > + > > switch (ecrc_policy) { > > case ECRC_POLICY_DEFAULT: > > return; > > -- > Sathyanarayanan Kuppuswamy > Linux Kernel Developer