From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932294Ab3AIX7n (ORCPT ); Wed, 9 Jan 2013 18:59:43 -0500 Received: from hydra.sisk.pl ([212.160.235.94]:36244 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932118Ab3AIX7m (ORCPT ); Wed, 9 Jan 2013 18:59:42 -0500 From: "Rafael J. Wysocki" To: Yinghai Lu Cc: Bjorn Helgaas , ACPI Devel Maling List , "linux-pci@vger.kernel.org" , Greg Kroah-Hartman , LKML , Tony Luck , "H. Peter Anvin" , Jiang Liu , Myron Stowe Subject: Re: [Alternative][PATCH] ACPI / PCI: Set root bridge ACPI handle in advance, v2 Date: Thu, 10 Jan 2013 01:05:24 +0100 Message-ID: <9771783.0zXIGEmDYn@vostro.rjw.lan> User-Agent: KMail/4.9.5 (Linux/3.8.0-rc2+; KDE/4.9.5; x86_64; ; ) In-Reply-To: References: <1558789.gX8cmBgyDV@vostro.rjw.lan> <1910593.f2RrgAtJJO@vostro.rjw.lan> 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 Wednesday, January 09, 2013 03:27:29 PM Yinghai Lu wrote: > On Wed, Jan 9, 2013 at 3:06 PM, Rafael J. Wysocki wrote: > > On Wednesday, January 09, 2013 03:16:59 PM Bjorn Helgaas wrote: > >> On Wed, Jan 9, 2013 at 2:33 PM, Rafael J. Wysocki wrote: > >> > From: Rafael J. Wysocki > >> > > >> > The ACPI handles of PCI root bridges need to be known to > >> > acpi_bind_one(), so that it can create the appropriate > >> > "firmware_node" and "physical_node" files for them, but currently > >> > the way it gets to know those handles is not exactly straightforward > >> > (to put it lightly). > >> > > >> > This is how it works, roughly: > >> > > >> > 1. acpi_bus_scan() finds the handle of a PCI root bridge, > >> > creates a struct acpi_device object for it and passes that > >> > object to acpi_pci_root_add(). > >> > > >> > 2. acpi_pci_root_add() creates a struct acpi_pci_root object, > >> > populates its "device" field with its argument's address > >> > (device->handle is the ACPI handle found in step 1). > >> > > >> > 3. The struct acpi_pci_root object created in step 2 is passed > >> > to pci_acpi_scan_root() and used to get resources that are > >> > passed to pci_create_root_bus(). > >> > > >> > 4. pci_create_root_bus() creates a struct pci_host_bridge object > >> > and passes its "dev" member to device_register(). > >> > > >> > 5. platform_notify(), which for systems with ACPI is set to > >> > acpi_platform_notify(), is called. > >> > > >> > So far, so good. Now it starts to be "interesting". > >> > > >> > 6. acpi_find_bridge_device() is used to find the ACPI handle of > >> > the given device (which is the PCI root bridge) and executes > >> > acpi_pci_find_root_bridge(), among other things, for the > >> > given device object. > >> > > >> > 7. acpi_pci_find_root_bridge() uses the name (sic!) of the given > >> > device object to extract the segment and bus numbers of the PCI > >> > root bridge and passes them to acpi_get_pci_rootbridge_handle(). > >> > > >> > 8. acpi_get_pci_rootbridge_handle() browses the list of ACPI PCI > >> > root bridges and finds the one that matches the given segment > >> > and bus numbers. Its handle is then used to initialize the > >> > ACPI handle of the PCI root bridge's device object by > >> > acpi_bind_one(). However, this is *exactly* the ACPI handle we > >> > started with in step 1. > >> > > >> > Needless to say, this is quite embarassing, but it may be avoided > >> > thanks to commit f3fd0c8 (ACPI: Allow ACPI handles of devices to be > >> > initialized in advance), which makes it possible to initialize the > >> > ACPI handle of a device before passing it to device_register(). > >> > > >> > Accordingly, add a new __weak routine, pcibios_root_bridge_prepare(), > >> > defaulting to an empty implementation that can be replaced by the > >> > interested architecutres (x86 and ia64 at the moment) with functions > >> > that will set the root bridge's ACPI handle before its dev member is > >> > passed to device_register(). Make both x86 and ia64 provide such > >> > implementations of pcibios_root_bridge_prepare() and remove > >> > acpi_pci_find_root_bridge() and acpi_get_pci_rootbridge_handle() that > >> > aren't necessary any more. > >> > > >> > Included is a fix for breakage on systems with non-ACPI PCI host > >> > bridges from Bjorn Helgaas. > >> > > >> > Signed-off-by: Rafael J. Wysocki > >> > >> Looks good to me! > >> > >> Acked-by: Bjorn Helgaas > > > > Thanks! > > > > I'll wait for comments from the others, if any, and put it into my acpi-scan > > branch after a couple of days. It doesn't need to be there technically, but > > it's kind of related. > > I tested it with acpi-scan and pci-root-bus-hotplug patchset, and it works well. > so > Acked-by: Yinghai Lu Thanks! > BTW, found one left over of change about ->acpi_handle==> ACPI_HANDLE.. Can you please submit that patch with a proper changelog? It is a mainline bug now (and a build regression for that matter), so I'd like to push the fix to Linus for v3.8-rc4. > Index: linux-2.6/drivers/acpi/glue.c > =================================================================== > --- linux-2.6.orig/drivers/acpi/glue.c > +++ linux-2.6/drivers/acpi/glue.c > @@ -311,7 +311,7 @@ static int acpi_platform_notify(struct d > if (!ret) { > struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; > > - acpi_get_name(dev->acpi_handle, ACPI_FULL_PATHNAME, &buffer); > + acpi_get_name(ACPI_HANDLE(dev), ACPI_FULL_PATHNAME, &buffer); > DBG("Device %s -> %s\n", dev_name(dev), (char *)buffer.pointer); > kfree(buffer.pointer); > } else > > > otherwise will get compiling error when enable acpi glue debug. Thanks, Rafael -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.