Hardware Power Management Controller for Low Latency Sleep Transitions
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Solution Overview
Problem
Current power management systems, such as those using ACPI standards, face challenges in reducing static power consumption and latency when transitioning between power states, particularly in the S3 system sleep state, which affects user experience due to prolonged re-establishment of network connectivity.
Innovation Solution
A power management controller that independently initiates a hardware system sleep state, S0A3, by monitoring system inactivity and using timer events to ensure low latency wake-up, allowing for maintenance of memory and communication connectivity, thereby reducing exit latency and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the system enters S3 sleep state to reduce power consumption, then static power consumption is reduced, but wake-up latency increases and network connectivity re-establishment takes minutes
Solution Approach 1:
The patent segments the system into two independent power management domains: OS-controlled software states (C-states for CPU, D-states for devices) and hardware system sleep states (S0A3, S0A2, S0A1). This segmentation allows the hardware layer to maintain connectivity and memory power independently of OS power management decisions, enabling fast wake-up from deep sleep states without requiring full system re-initialization.
Solution Approach 2:
The patent introduces a hardware system sleep state control mechanism as an intermediary layer between the OS and physical hardware. This intermediary (the hardware system sleep state controller) can independently manage power states, maintain memory power, and preserve connectivity without OS intervention, thereby resolving the contradiction between deep power savings and fast wake-up by mediating between OS power management and hardware requirements.
2Loss of time
If the system maintains memory power and connectivity in S3 state, then wake-up latency is reduced, but power consumption increases
Solution Approach 1:
The patent implements dynamic power management where the hardware system sleep state controller can independently adjust power states of different system components. Memory power and connectivity can be dynamically maintained or reduced based on actual system needs rather than OS power state, allowing the system to adapt power consumption to actual requirements and achieve fast wake-up only when necessary.
Solution Approach 2:
The patent changes the power management paradigm by introducing hardware-controlled system sleep states (S0A3, S0A2, S0A1) with different power consumption and wake-up characteristics. These states allow fine-grained control over power parameters (memory power, connectivity power) independent of OS state, enabling optimization of both power consumption and wake-up latency based on specific operational requirements.
3Ease of operation
If ACPI OS-controlled power management is used, then software can control power states, but hardware system sleep state transitions are delayed and affect user experience
Solution Approach 1:
The patent segments power management control into two independent layers: OS-controlled software states (C-states, D-states) and hardware-controlled system sleep states (S0A3, S0A2, S0A1). This segmentation allows software to maintain control over logical power states while hardware independently manages physical sleep transitions, eliminating the delay caused by OS processing and enabling immediate hardware response to sleep/wake commands.
Solution Approach 2:
The patent introduces a hardware system sleep state controller as an intermediary that translates OS power management intent into immediate hardware actions. This intermediary handles the time-critical hardware state transitions independently of OS software processing, thereby maintaining software control authority while eliminating software-induced latency in hardware sleep state transitions.
Data Source
AI summary
A processor includes a processor core and a power management controller operable to receive a timer event, store the timer event, generate a hardware system sleep command to enter a hardware system sleep state, and restore the timer event upon exiting from the hardware system sleep state.