Firmware Sleep Mapper for Secure Hybrid Standby Power Management
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Solution Overview
Problem
Current computing devices face challenges in energy efficiency, particularly with the support for ACPI S3 sleep state being deprecated in many modern processors, which affects battery life in portable devices and compute density and thermal management in servers, while also introducing complexity in hardware and firmware design.
Innovation Solution
Implementing a sleep mapper firmware shim that traps the ACPI S3 sleep request and instead enters a low-power idle state like S0ix, allowing for improved power management without requiring processor reset or firmware boot flow, thus maintaining compatibility with existing operating systems and simplifying hardware design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If ACPI S3 sleep state is supported, then power management capability is improved, but hardware and firmware complexity increases
Solution Approach 1:
The patent introduces a firmware shim as an intermediary layer between the operating system and the hardware power management subsystem. This shim intercepts ACPI S3 sleep requests and translates them into alternative low-power states (such as S0ix), thereby maintaining power management functionality while avoiding the complexity of direct S3 implementation. The shim acts as a mediator that preserves software compatibility without requiring complex hardware S3 support.
2Duration of action of moving object
If ACPI S3 sleep state is supported, then sleep functionality is improved, but processor reset and firmware boot flow are required which increases sleep and resume times
Solution Approach 1:
The patent creates a simplified copy or approximation of the S3 sleep functionality using existing low-power states like S0ix. Instead of implementing the full S3 state with its associated processor reset and firmware boot requirements, the system uses a lightweight alternative that mimics the essential sleep functionality. This copied approach preserves the ability to enter and exit sleep states while dramatically reducing the time penalties associated with full processor resets.
3Loss of energy
If modern low-power states like S0ix are used, then power consumption is reduced, but operating system or software support is required which increases software complexity
Solution Approach 1:
The firmware shim serves as an intermediary that shields the operating system from the complexity of modern low-power state management. Rather than requiring the OS to directly manage S0ix or other contemporary low-power states, the shim handles the translation and coordination, presenting a simplified interface to the OS while managing the complex state transitions in the background. This reduces the software complexity burden on the operating system.
4Device complexity
If ACPI S3 sleep state is deprecated, then hardware design is simplified, but compatibility with existing operating systems that invoke S3 state is lost
Solution Approach 1:
Instead of modifying operating systems to stop using S3 requests, the patent inverts the approach by having the firmware shim actively intercept and translate S3 requests from existing operating systems. This allows legacy OS code to continue invoking S3 without modification, while the shim redirects these calls to alternative low-power states. The inversion principle enables backward compatibility to be maintained at the software level even as hardware S3 support is deprecated.
Data Source
AI summary
Technologies for secure hybrid standby power management include a computing device with a processor supporting low-power idle standby. An operating system writes a power management sleep request, such as an ACPI S3 request, to a power management control register of the computing device. The processor traps the write to the power management control register and executes a firmware sleep mapper that causes the processor to enter an idle standby power state such as S0ix. The firmware sleep mapper may be included in a firmware isolated memory region. The address of the firmware sleep mapper may be included in a model-specific register of the processor. The processor may verify the firmware sleep mapper before execution. In response to a wake event, the processor resumes the firmware sleep mapper, which switches the processor to real mode and jumps to a waking vector of the operating system. Other embodiments are described and claimed.