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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 6FC36C433DF for ; Mon, 18 May 2020 15:54:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F0DC207D8 for ; Mon, 18 May 2020 15:54:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728370AbgERPyp (ORCPT ); Mon, 18 May 2020 11:54:45 -0400 Received: from foss.arm.com ([217.140.110.172]:43270 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727007AbgERPyp (ORCPT ); Mon, 18 May 2020 11:54:45 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 36DDF106F; Mon, 18 May 2020 08:54:44 -0700 (PDT) Received: from e121166-lin.cambridge.arm.com (e121166-lin.cambridge.arm.com [10.1.196.255]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 71C243F52E; Mon, 18 May 2020 08:54:42 -0700 (PDT) Date: Mon, 18 May 2020 16:54:35 +0100 From: Lorenzo Pieralisi To: Bjorn Helgaas Cc: Vidya Sagar , jingoohan1@gmail.com, gustavo.pimentel@synopsys.com, Andrew Murray , bhelgaas@google.com, thierry.reding@gmail.com, jonathanh@nvidia.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, kthota@nvidia.com, mmaddireddy@nvidia.com, sagar.tv@gmail.com, Alan Mikhak Subject: Re: [PATCH] PCI: dwc: Warn only for non-prefetchable memory resource size >4GB Message-ID: <20200518155435.GA2299@e121166-lin.cambridge.arm.com> References: <20200513190855.23318-1-vidyas@nvidia.com> <20200513223508.GA352288@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200513223508.GA352288@bjorn-Precision-5520> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 13, 2020 at 05:35:08PM -0500, Bjorn Helgaas wrote: > [+cc Alan; please cc authors of relevant commits, > updated Andrew's email address] > > On Thu, May 14, 2020 at 12:38:55AM +0530, Vidya Sagar wrote: > > commit 9e73fa02aa009 ("PCI: dwc: Warn if MEM resource size exceeds max for > > 32-bits") enables warning for MEM resources of size >4GB but prefetchable > > memory resources also come under this category where sizes can go beyond > > 4GB. Avoid logging a warning for prefetchable memory resources. > > > > Signed-off-by: Vidya Sagar > > --- > > drivers/pci/controller/dwc/pcie-designware-host.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c > > index 42fbfe2a1b8f..a29396529ea4 100644 > > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > > @@ -366,7 +366,8 @@ int dw_pcie_host_init(struct pcie_port *pp) > > pp->mem = win->res; > > pp->mem->name = "MEM"; > > mem_size = resource_size(pp->mem); > > - if (upper_32_bits(mem_size)) > > + if (upper_32_bits(mem_size) && > > + !(win->res->flags & IORESOURCE_PREFETCH)) > > dev_warn(dev, "MEM resource size exceeds max for 32 bits\n"); > > pp->mem_size = mem_size; > > pp->mem_bus_addr = pp->mem->start - win->offset; That warning was added for a reason - why should not we log legitimate warnings ? AFAIU having resources larger than 4GB can lead to undefined behaviour given the current ATU programming API. Alan ? I want to understand what's the best course of action before merging these patches. Lorenzo