ACPI-based Hotplug of PCI and Other Devices - Rafael Wysocki, Intel OTC
ACPI provides a consistent framework for implementing platform-specific out-of-band signaling of hotplug events, such as device hot-add and hot-remove and software-triggered device ejection methods. In principle, hotplug events may be signaled for every device represented by an object in the ACPI namespace. The Linux kernel has been supporting that interface for a long time, but until relatively recently it was focused on isolated use cases, such as PCI devices in separate slots etc. However, the introduction of new hardware technologies allowing, for example, the entire CPU packages to be hot-removed and hot-added or the entire segments of PCI bus to be manipulated, like in the Intel Thunderbolt case, caused the focus to be moved towards supporting more complicated hotplug scenarios. As a result, an effort is under way to consolidate the ACPI-based hotplug of devices and make it more capable of supporting the new use cases. I'd like to outline what has been achieved already in that area and discuss the remaining challenges. http://www.linuxplumbersconf.org/2013/