blob: aca928fab027a5cc5104dad1c19ae23c57853883 [file] [log] [blame]
.. SPDX-License-Identifier: GPL-2.0
Low Power Idle Table (LPIT)
To enumerate platform Low Power Idle states, Intel platforms are using
Low Power Idle Table (LPIT). More details about this table can be
downloaded from:
Residencies for each low power state can be read via FFH
(Function fixed hardware) or a memory mapped interface.
On platforms supporting S0ix sleep states, there can be two types of
- CPU PKG C10 (Read via FFH interface)
- Platform Controller Hub (PCH) SLP_S0 (Read via memory mapped interface)
The following attributes are added dynamically to the cpuidle
sysfs attribute group::
The "low_power_idle_cpu_residency_us" attribute shows time spent
by the CPU package in PKG C10
The "low_power_idle_system_residency_us" attribute shows SLP_S0
residency, or system time spent with the SLP_S0# signal asserted.
This is the lowest possible system power state, achieved only when CPU is in
PKG C10 and all functional blocks in PCH are in a low power state.