On Sun, Dec 16, 2012 at 2:25 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > 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(). > Namely, if pci_acpi_scan_root() could easily pass the root bridge's > ACPI handle to pci_create_root_bus(), the latter could set the ACPI > handle in its struct pci_host_bridge object's "dev" member before > passing it to device_register() and steps 6-8 above wouldn't be > necessary any more. > > To make that happen I decided to repurpose the 4th argument of > pci_create_root_bus(), because that allowed me to avoid defining > additional callbacks or similar things and didn't seem to impact > architectures without ACPI substantially. > > Only x86 and ia64 are affected directly, there should be no > functional changes resulting from this on other architectures. that is good one to avoid that find_root_bridge... > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > --- > > Should apply to the current Linus' tree, boots correctly on x86(-64). > > Thanks, > Rafael > > --- > arch/ia64/pci/pci.c | 5 ++++- > arch/powerpc/kernel/pci-common.c | 3 ++- > arch/sparc/kernel/pci.c | 3 ++- > arch/x86/pci/acpi.c | 5 ++++- > drivers/acpi/pci_root.c | 18 ------------------ > drivers/pci/pci-acpi.c | 19 ------------------- > drivers/pci/probe.c | 16 +++++++++++----- > include/acpi/acpi_bus.h | 1 - > include/linux/pci.h | 9 ++++++++- > 9 files changed, 31 insertions(+), 48 deletions(-) you need to update other arch for pci_create_root_bus arch/powerpc/kernel/pci-common.c: bus = pci_create_root_bus(hose->parent, hose->first_busno, arch/s390/pci/pci.c: zdev->bus = pci_create_root_bus(NULL, ZPCI_BUS_NR, &pci_root_ops, arch/sparc/kernel/pci.c: bus = pci_create_root_bus(parent, pbm->pci_first_busno, pbm->pci_ops, drivers/parisc/dino.c: dino_dev->hba.hba_bus = bus = pci_create_root_bus(&dev->dev, drivers/parisc/lba_pci.c: pci_create_root_bus(&dev->dev, lba_dev->hba.bus_num.start, > > Index: linux/arch/x86/pci/acpi.c > =================================================================== > --- linux.orig/arch/x86/pci/acpi.c > +++ linux/arch/x86/pci/acpi.c > @@ -450,6 +450,7 @@ struct pci_bus * __devinit pci_acpi_scan > LIST_HEAD(resources); > struct pci_bus *bus = NULL; > struct pci_sysdata *sd; > + struct pci_root_sys_info si; > int node; > #ifdef CONFIG_ACPI_NUMA > int pxm; > @@ -486,6 +487,8 @@ struct pci_bus * __devinit pci_acpi_scan > sd = &info->sd; > sd->domain = domain; > sd->node = node; > + si.acpi_node.handle = device->handle; > + si.sysdata = sd; maybe you can try to have si.acpi_handle directly ? Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
