[PATCH] Catch notification of memory add event of ACPI via container driver. (avoid redundant call add_memory)
When acpi_memory_device_init() is called at boottime to register struct
memory acpi_memory_device, acpi_bus_add() are called via
acpi_driver_attach().
But it also calls ops->start() function. It is called even if the memory
blocks are initialized at early boottime. In this case add_memory() return
-EEXIST, and the memory blocks becomes INVALID state even if it is normal.
This is patch to avoid calling add_memory() for already available memory.