LinuxCon Europe + CloudOpen Europe

One of the important features of ACPI is the ability to handle platform-specific out-of-band signaling of device hot-plug events, which in principle is possible for any device represented in the ACPI namespace. Moreover, dependencies between devices can be taken into account and platform-specific methods of device ejection may be provided. The Linux kernel has supported that interface for a long time, but in a limited way. In particular, it did not allow hot removal to fail gracefully and it did not really support hot-plug operations involving multiple devices of different types. Currently, an effort is under way to integrate ACPI-based device hot-plug support in the kernel into a consistent framework capable of handling all of the possible hot-plug scenarios. I will discuss the problems that had to be overcome, the progress already made and future development plans in that area.