On Wed, Jan 20, 2016 at 02:40:08PM +0100, Tomasz Nowicki wrote: [...] > >>>>+ /* Root bridge device needs to be sure of parent ACPI type */ > >>>>+ ACPI_COMPANION_SET(&device->dev, device); > >>> > >>>I do not understand why the code above is needed, can you elaborate > >>>please ? > >>> > >> > >>This makes sure that device->dev can be identified as ACPI device, > >>so we can use to_acpi_device_node() and assign companion safely > >>below. > > > >I do not follow. If you refer to the fwnode handle type, that is > >already set by ACPI core code (before acpi_pci_root_add() is called, > >in acpi_init_device_object()). > > acpi_init_device_object() sets ACPI fwnode handle type only for > "device", but not for "device->dev" which is what is passed as an > argument to pci_create_root_bus(). > > Without ACPI_COMPANION_SET(&device->dev, device) here, no one can be > sure if we have ACPI device in pci_create_root_bus(). Ok, got it. The question is whether this should be done in ACPI core instead (is there a reason why it should *not* be done ?), but I now understand your point. Thanks, Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
