From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756412AbeEJCpF (ORCPT ); Wed, 9 May 2018 22:45:05 -0400 Received: from mail-oi0-f54.google.com ([209.85.218.54]:36854 "EHLO mail-oi0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756235AbeEJCpD (ORCPT ); Wed, 9 May 2018 22:45:03 -0400 X-Google-Smtp-Source: AB8JxZqizOVrB9x7a1jRw4o8emqxtoNZOW8quPq/eBZmYVf9fatAIPUaKm7HywIbqOmrkVsNQWlXiA== Subject: Re: [PATCH] PCI: Check whether bridges allow access to extended config space To: Gilles Buloz Cc: Bjorn Helgaas , Bjorn Helgaas , linux-pci , "Minghuan.Lian@nxp.com" , "linux-arm-kernel@lists.infradead.org" , Ard Biesheuvel , "linux-kernel@vger.kernel.org" , Sinan Kaya References: <20180504200600.GA9529@bhelgaas-glaptop.roam.corp.google.com> <20180507215619.GA161390@bhelgaas-glaptop.roam.corp.google.com> <5AF2E91E.3030804@kontron.com> From: Frederick Lawler Message-ID: <4d54d03c-e450-5ae2-853f-1d4fe4ed3b85@fredlawl.com> Date: Wed, 9 May 2018 21:44:58 -0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 PostboxApp/6.0.7.1 MIME-Version: 1.0 In-Reply-To: <5AF2E91E.3030804@kontron.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Gilles Buloz wrote: > Here are full dmesg + lspci -vv + ... for the following cases : > - 4.17-rc1_probe_failed_without_pcieaspmoff.txt : I get a broken PCI config at most boots, without pcie_aspm=off > - 4.17-rc1_probe_ok_without_pcieaspmoff.txt : I get a correct PCI config at some boots, even without pcie_aspm=off > - 4.17-rc1_probe_always_ok_with_pcieaspmoff.txt : I get a correct PCI config at all boots when using pcie_aspm=off > - 4.1.35_probe_always_ok_without_pcieaspmoff.txt : I get a correct PCI config at all boots when using kernel 4.1.35-rt41 (from NXP > Yocto BSP), even without pcie_aspm=off > > I noticed these strange things : > - with 4.17-rc1, without pcie_aspm=off, the kernel is hanging during ~1 second : > - before line "ASPM: Could not configure common clock" when PCI config is OK > - or before line "bridge configuration invalid ([bus ff-ff]), reconfiguring" when PCI config is NOT OK > (the FFs in "[bus ff-ff]" seems side effects of read returning ~0 because device is off) > - no such hang when pcie_aspm=off is used > - applying reverse patch for "PCI/ASPM: Don't warn if already in common clock mode" > (commit 04875177dbe034055f23960981ecf6fb8ea1d638) does not give more message I submitted this as a bug here: https://bugzilla.kernel.org/show_bug.cgi?id=199671 Thanks, Fred