PCIe Storage Device L1.2 Power Sub-State Entry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current data storage devices on a PCIe network cannot transition to L1.1 or L1.2 power sub-states if not all devices on the network support these states, leading to increased idle power consumption as they remain in the L1 power state, which is not suitable for mobile devices and high-performance computing due to long recovery times.
Innovation Solution
A PCI FW register configures a CLKREQ de-assert signal to a MAC of the data storage device, independent of the host's power state, allowing the device to enter L1 sub-states like L1.2, with a sensor remaining active to detect a wake-up signal for transitioning to a higher power state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If all devices on a PCIe network support L1 power sub-states, then power consumption is reduced and recovery time is improved, but device compatibility and network-wide adoption are limited
Solution Approach 1:
The data storage device independently determines and transitions to L1 power sub-states without requiring host device support or coordination. The device autonomously manages its own power state transitions, enabling it to enter low-power states even when other devices on the network do not support them.
Solution Approach 2:
The patent separates the power management capability from the host device control, allowing individual devices to independently manage their own power states. This segmentation enables each device to operate in L1 sub-states autonomously rather than requiring network-wide coordination.
2Use of energy by moving object
If L2 and L3 power states are used, then power consumption is reduced, but recovery time to active state increases to milliseconds
Solution Approach 1:
The patent changes the power state parameters by introducing L1 sub-states (L1.1, L1.2) that offer intermediate power consumption levels between L0 and L2/L3. These sub-states provide lower power consumption closer to L2/L3 while maintaining faster recovery times closer to L0, achieving an optimal balance through parameter adjustment.
3Loss of time
If L1 power state is used, then recovery time to active state is fast, but power consumption remains relatively large
Solution Approach 1:
The patent introduces dynamic power sub-states (L1.1, L1.2) within the L1 power state hierarchy. These dynamic sub-states allow the device to adjust its power consumption and recovery characteristics based on operational needs, providing flexibility to optimize between power savings and recovery speed.
Data Source
AI summary
A method and apparatus for data storage devices, or other devices that are L1 sub-state capable, to enter these sub-states while on the same network or bus as a device not enabled for transition to an L1 power sub-state. According to certain embodiments, a PCI FW register is configured to place a CLKREQ de-assert signal to a MAC of the data storage device, independent of the power state of the host. The CLKREQ de-assert signal causes the MAC to place the data storage device in an L1 power substate such as L1.2. A sensor of the controller remains active to detect a wakeup signal from the host that causes the data storage device to transition to a higher power state.