Abstract: The present disclosure generally relates to reducing exit latency when transitioning from non-operational power states. Before entering a non-operational power state, specific data in databases and/or tables can be identified as being recently utilized by the host device. In addition to saving the databases and/or tables, a recovery code is also stored to identify that specific data. Upon transitioning back to an operational power state, the recovery code is detected and the specific data can be recovered rather than recovering the entire database and/or table. Data not identified in the recovery code need not be recovered from always-on memory. In so doing, when transitioning back to an operational power state, the latency will be reduced compared to a situation where all data is stored in always-on memory.

Abstract: 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.

Abstract: 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.

Abstract: The present disclosure describes methods and systems for data storage or other devices that are L1 sub-state capable, to be able to enter these sub-states while on the same network or bus as a device not enabled for transition to an L1 sub-state. In some embodiments, when an LTSSM circuit in a MAC of a PCIe device indicates an L1 idle state, an L1 sub-state (L1SS) timer is initiated in a CLKREQ on the device. Upon expiration of the timer, a CLKREQ_in emulator de-asserts its signal on the MAC, causing the MAC to enter an L1SS.