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=-8.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,USER_IN_DEF_DKIM_WL 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 486B9C43381 for ; Mon, 4 Mar 2019 20:29:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1294C20823 for ; Mon, 4 Mar 2019 20:29:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="sLoCgsAR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726655AbfCDU3i (ORCPT ); Mon, 4 Mar 2019 15:29:38 -0500 Received: from mail-wm1-f68.google.com ([209.85.128.68]:40870 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726615AbfCDU3g (ORCPT ); Mon, 4 Mar 2019 15:29:36 -0500 Received: by mail-wm1-f68.google.com with SMTP id g20so429291wmh.5 for ; Mon, 04 Mar 2019 12:29:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Ml2tdFA+5PlAJQBN6XbzQLx/7woCXwX7t6b6wUqam8o=; b=sLoCgsARwe8UHmk7A0Yg69rz227Drq9/UsbCHKeeJbwlSibGInLFET2GkHejSd6AVj LdW6RWKkUFODnjWMyk5aOS1fjdF274+/7H+FFDU/v91WispFNJO3Gg74i9oArAz0IwB+ 2QPUqlRAzysjyO1Zr3DytCMUGiLkemShez9JESNoyd18j2cxfISi1ZONdB7ltcsUi0Yp HVOtKNXTgKcdWwibCvdOPqcMFPkLpiDdkT5XUvKRwUMZEgaJQNwPZtcbDa9f7PbS5CUS Jj5BDmTYUw4VoMGcSwCJsmG3xoevKY/b14Mz6A6DI2XZFfQjrIk1IyjnBEmVvC1APPBs Mk/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Ml2tdFA+5PlAJQBN6XbzQLx/7woCXwX7t6b6wUqam8o=; b=M7ifLsgV1HDg9NYu9fMzdQIasJQox0WgguYdDy6zb8ECcMlWqE7QI0w6oBTe+DiBNA w/htgIzQjPvCp9VBUkr7LwlPKX6XpAqcOqc0Ph8RRPIkIFAY/MLilyiOnfdDSvvOI3qn NOfPcoLxyhLLALupHcr9R6eVpE2Ox7zfDEA3HlgUZ0MsOF5u3/UB9DtEfI7ym8IPz6ft wJ7q5K8OA0XnOwbq8YgfbRT6Vgpqodf54o3Tq/rPBbYj44AsP69mpCJnAFcOBRXMckMp lsIv2xwu1eq0FTrWWlDxEb7XC89hK5pYW4otH4XiyiQp+rUCNtiEYh6xKMBBSOqCjNLi 4zZA== X-Gm-Message-State: APjAAAVWd0PJ+PgomNJ7naMQOkFCgaXLkqvt1n32w4u99p10+FtZttAQ Oz4D2Tu2ClrzCSGCepi9nNWry+5OkGeBzcy4PYGO X-Google-Smtp-Source: APXvYqxgO/jYYpeuzkpREkIfXLetZXue0MaaWz0cvXBcEHZV7bOZO+trWaAWV4WFnhfzZbaKjyhig/yX9n8odFvgcwo= X-Received: by 2002:a1c:6409:: with SMTP id y9mr583649wmb.68.1551731374113; Mon, 04 Mar 2019 12:29:34 -0800 (PST) MIME-Version: 1.0 References: <20190214170028.27862-1-logang@deltatee.com> <20190304002351.GA26569@google.com> <3e45b4ab-e848-cf3b-624f-121ad58b0250@deltatee.com> In-Reply-To: From: Bjorn Helgaas Date: Mon, 4 Mar 2019 14:29:22 -0600 Message-ID: Subject: Re: [PATCH 1/2] PCI: Prevent 64-bit resources from being counted in 32-bit bridge region To: Logan Gunthorpe Cc: Bjorn Helgaas , Linux Kernel Mailing List , Linux PCI , Kit Chow , Yinghai Lu Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 4, 2019 at 2:21 PM Logan Gunthorpe wrote: > On 2019-03-04 1:11 p.m., Bjorn Helgaas wrote: > > On Mon, Mar 4, 2019 at 1:21 PM Logan Gunthorpe wrote: > >> On 2019-03-03 5:23 p.m., Bjorn Helgaas wrote: > >>> Sorry for the delay. This code gives a headache. I still remember > >>> my headache from the last time we touched it. Help me understand > >>> what's going on here. > >> > >> Yes, this code gave me a headache debugging it too. And it's not the > >> first time I've tried to figure out what's going on with it because it > >> often just prints noisy messages that look like errors. I think I > >> understand it better now but it's something that's a bit fleeting and > >> easy to forget the details of. There may also be other solutions to this > >> problem. > > > > Thanks for the explanation below. I haven't worked through it yet, but I will. > > > > Obviously it would be far better than an explanation if we could > > simplify the code (and the noisy messages) such that it didn't > > *require* so much explanation. > > I agree, but reworking this code scares me and I suspect it was designed > this way for a reason. I'm guessing there are a lot of corner cases and > unusual bios issues this stuff works around. We might end up fixing a > some cases and breaking a bunch of other cases. Scares me too, which is one reason I haven't done anything about it. I didn't mean to suggest that you should rework it for *this* issue. I just keep hoping that we can chip away at teensy pieces and in ten or twenty years maybe make some headway. Bjorn