Intel Corporation
MEMORY POWER MANAGEMENT METHOD AND APPARATUS

Abstract:

A mechanism where the locked pages are saved and restored by a hardware accelerator which is transparent to the OS. Prior to standby entry, the OS puts all DMA capable devices in the lowest-powered device low-power state after disabling bus mastering. The OS flushes all pageable memory to an NVM (in segments that are kept in self-refresh) and provides a list of pinned and locked pages in the DRAM to a power management controller (p-unit). The p-unit checks for all Bus Mastering DMA to be turned off and checks if a next OS timer wake event (TNTE) is greater than a threshold, to decide whether to enable or disable PASR or MPSM in Standby. If the conditions are met, the p-unit triggers a hardware accelerator to consolidate the pinned and locked pages in the DRAM to certain segment(s) of the DRAM during standby states, making it transparent to the OS.