Rafael J. Wysocki 6c0cc950ae ACPI / PCI: Set root bridge ACPI handle in advance ... 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 <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>		2013-01-13 17:14:28 -07:00
..
asm	ACPI / PCI: Set root bridge ACPI handle in advance	2013-01-13 17:14:28 -07:00
uapi/asm	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal	2012-12-20 18:05:28 -08:00