On Wed, Aug 8, 2012 at 8:44 AM, Jiang Liu <liuj97@xxxxxxxxx> wrote: > On 08/08/2012 07:38 AM, Toshi Kani wrote: >> It is nice to see redundant ACPI namespace walks removed from the ACPI >> drivers. But why do you need to add a new enumerator to create the >> acpihp_slot tree, in addition to the current acpi_device tree? I'd >> prefer hotplug features to be generally integrated into the current ACPI >> core code and data structures, instead of adding a new layer on top of >> it. > The idea comes from PCI hotplug framework, which has an concepts of PCI > hotplug slot and PCI device. For system device hotplug, we could follow > the same model as PCI by abstracting control points as slots. By introducing > of hotplug slot, we could: > > 1) Report all hotplug slots and slot's capabilities to user, no matter whether > there are devices connecting to a slot. If we integrate hotplug functionality > into current ACPI device tree, the slot (or device) is only visible when the > connected devices are enabled. In PCI, the idea of a slot is a pretty explicit -- you can look at the capabilities of a bridge device and see whether it supports hot-add of a device below it. Is it the same way in ACPI? My impression is that it is not: there will be a parent ACPI device under which a new device can be added, but you might not be able to tell by looking at the parent device that hot-add is possible. I thought the platform could just give us a Notify event on the parent, asking us to rescan the namespace below it and potentially discover new devices. -- 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
