From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756967Ab3K0AuD (ORCPT ); Tue, 26 Nov 2013 19:50:03 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:49988 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753069Ab3K0Atz (ORCPT ); Tue, 26 Nov 2013 19:49:55 -0500 From: "Rafael J. Wysocki" To: Toshi Kani Cc: ACPI Devel Maling List , LKML , Linux PCI , Bjorn Helgaas , Aaron Lu Subject: Re: [PATCH 0/4] ACPI / bind: Simplify child devices lookup Date: Wed, 27 Nov 2013 02:02:43 +0100 Message-ID: <8065346.ZtkoVh8DW8@vostro.rjw.lan> User-Agent: KMail/4.10.5 (Linux/3.12.0-rc6+; KDE/4.10.5; x86_64; ; ) In-Reply-To: <1385512408.1791.196.camel@misato.fc.hp.com> References: <2610478.KxPMyuOMok@vostro.rjw.lan> <3773077.bfZR2z09sY@vostro.rjw.lan> <1385512408.1791.196.camel@misato.fc.hp.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, November 26, 2013 05:33:28 PM Toshi Kani wrote: > On Wed, 2013-11-27 at 01:27 +0100, Rafael J. Wysocki wrote: > > On Tuesday, November 26, 2013 05:00:42 PM Toshi Kani wrote: > > > On Mon, 2013-11-25 at 01:09 +0100, Rafael J. Wysocki wrote: > > > > Hi, > > > > > > > > The following series of four patches (on top of current linux-pm.git/bleeding-edge) > > > > rework child device lookup in drivers/acpi/glue.c and related things: > > > > > > > > [1/4] ACPI / bind: Simplify child device lookup > > > > [2/4] PCI/ ACPI: Use acpi_find_child_device() for child device lookup > > > > [3/4] ACPI / bind: Redefine acpi_get_child() > > > > [4/4] ACPI / bind: Redefine acpi_preset_companion() > > > > > > This patchset caused the attached panic during boot on a system. > > > acpi_pci_find_device() called acpi_find_child_device() with > > > ACPI_COMPANION(dev->parent) being a NULL pointer when scanning bus 0xf. > > > > > > This bus 0xf seems to be a chipset internal bus, which is not intended > > > for the OS to use. Therefore, ACPI does not list its PCI bridge device. > > > > > > # lspci -tv > > > : > > > +-[0000:0f]-+-08.0 Intel Corporation Ivytown QPI Link 0 > > > | +-08.2 Intel Corporation Ivytown QPI Link 0 > > > : > > > > > > However, pcibios_fixup_peer_bridges(), called from pci_subsys_init(), > > > finds this bus as it scans all the buses from 0 to pcibios_last_bus. > > > Hence, this dev->parent does not have an associated ACPI device object. > > > > Thanks for the report! > > > > I've dropped the patches from bleeding-edge for now. > > > > Does "[1/4] ACPI / bind: Simplify child device lookup" alone work on that > > system? > > Yes, the system boots fine with 1/4 alone. Thanks! Can you please check if the following modified [2/4] also works on top of it? Rafael --- From: Rafael J. Wysocki Subject: PCI / ACPI: Use acpi_find_child_device() for child devices lookup It is much more efficient to use acpi_find_child_device() for child devices lookup in acpi_pci_find_device() and pass ACPI_COMPANION(dev->parent) to it directly instead of obtaining ACPI_HANDLE() of ACPI_COMPANION(dev->parent) and passing it to acpi_find_child() which has to run acpi_bus_get_device() to obtain ACPI_COMPANION(dev->parent) from that again. Signed-off-by: Rafael J. Wysocki Reviewed-by: Aaron Lu --- drivers/acpi/glue.c | 3 +++ drivers/pci/pci-acpi.c | 16 ++++++++++------ 2 files changed, 13 insertions(+), 6 deletions(-) Index: linux-pm/drivers/pci/pci-acpi.c =================================================================== --- linux-pm.orig/drivers/pci/pci-acpi.c +++ linux-pm/drivers/pci/pci-acpi.c @@ -309,7 +309,8 @@ void acpi_pci_remove_bus(struct pci_bus static int acpi_pci_find_device(struct device *dev, acpi_handle *handle) { struct pci_dev *pci_dev = to_pci_dev(dev); - bool is_bridge; + struct acpi_device *adev; + bool check_children; u64 addr; /* @@ -317,14 +318,17 @@ static int acpi_pci_find_device(struct d * is set only after acpi_pci_find_device() has been called for the * given device. */ - is_bridge = pci_dev->hdr_type == PCI_HEADER_TYPE_BRIDGE + check_children = pci_dev->hdr_type == PCI_HEADER_TYPE_BRIDGE || pci_dev->hdr_type == PCI_HEADER_TYPE_CARDBUS; /* Please ref to ACPI spec for the syntax of _ADR */ addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn); - *handle = acpi_find_child(ACPI_HANDLE(dev->parent), addr, is_bridge); - if (!*handle) - return -ENODEV; - return 0; + adev = acpi_find_child_device(ACPI_COMPANION(dev->parent), addr, + check_children); + if (adev) { + *handle = adev->handle; + return 0; + } + return -ENODEV; } static void pci_acpi_setup(struct device *dev) Index: linux-pm/drivers/acpi/glue.c =================================================================== --- linux-pm.orig/drivers/acpi/glue.c +++ linux-pm/drivers/acpi/glue.c @@ -106,6 +106,9 @@ struct acpi_device *acpi_find_child_devi struct acpi_device *adev, *ret = NULL; int ret_score = 0; + if (!parent) + return NULL; + list_for_each_entry(adev, &parent->children, node) { unsigned long long addr; acpi_status status;