Providing a deterministic idle time window for an idle state of a device

• US 7,752,473 B1
• Filed: 03/20/2006
• Issued: 07/06/2010
• Est. Priority Date: 03/20/2006
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Harriman, David J., Kwa, Seh W.
• Primary Examiner(s): Cao; Chun
• Application Number:
  US11/384,681
• Time in Patent Office: 1,569 Days
• Field of Search: 713/320, 713/323
• US Class Current: 713/323
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/3215 Monitoring of peripheral devices
• CPC Class Codes: G06F 1/3246 by software initiated power-off
• CPC Class Codes: G06F 1/3287 by switching off individual functional units in the computer system
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

In one embodiment, the present invention includes a method for receiving at a target device a request for a deterministic idle window from an initiator device via an interconnect, determining whether to accept the request, e.g., based on an anticipated time until the target device'"'"'s next activity, and sending an acknowledgment to the initiator device based on the determination. The initiator and target devices may enter an extended idle state based on the determination. Other embodiments are described and claimed.

Claims

1. A method comprising:

receiving at a target device a request for a deterministic idle time window from an initiator device via an interconnect;

determining whether to accept the request; and

acknowledging the request to the initiator device based on the determination, including sending an acknowledgement message indicating an idle time window having a different length than the deterministic idle time window.

2. The method of claim 1, wherein acknowledging the request comprises declining the request if the target device does not have an available idle time window of a length equal or less than the deterministic idle time window.

3. The method of claim 1, further comprising receiving the request via a serial interconnect coupled between the target device and the initiator device, wherein the target device comprises a peripheral device of a mobile system and the initiator device comprises an interface hub of the mobile system.

4. The method of claim 1, further comprising entering a power management mode for an interface of the initiator device upon receipt of the acknowledgment.

5. The method of claim 4, further comprising disabling a phase-locked loop of a platform including the initiator device in the power management mode.

6. The method of claim 1, wherein determining whether to accept the request comprises determining in the target device an anticipated time until a next activity of the target device.

7. The method of claim 6, further comprising accepting the request if the anticipated time is greater than a threshold, the threshold corresponding to a period for entry into and exit from a power management mode for the target device.

8. The method of claim 1, further comprising entering into a power management mode on an interface of the target device based on an electrical state of the interconnect.

9. The method of claim 1, further comprising transmitting a second request for a second deterministic idle time window to the initiator device at a later time, wherein at the later time the target device initiates and transmits the second request to the initiator device.

10. An apparatus comprising:

a first device to transmit a request for a deterministic idle time window to a second device coupled to the first device via an interconnect, wherein the first device is to transmit the request based on a state of the interconnect, and the first device is to enter into a low power state for a second idle time window less than the deterministic idle time window if the second device transmits an acknowledgment for the second idle time window.

11. The apparatus of claim 10, wherein the state of the interconnect corresponds to an inactive status of the interconnect.

12. The apparatus of claim 10, wherein the first device comprises a component of a platform and the second device comprises a peripheral device coupled to the platform, the platform comprising a mobile system.

13. The apparatus of claim 12, wherein the component comprises a hub interface having a first link interface to the interconnect and the peripheral device comprises a wireless adapter having a second link interface to the interconnect.

14. The apparatus of claim 13, wherein the first link interface is to enter a power management mode upon receipt of an acknowledgment to the request from the peripheral device, and wherein the second link interface is to enter a power management mode upon detection of an electrical idle state of the interconnect.

15. The apparatus of claim 10, wherein a platform including the first device is to enter a power management mode in which at least one platform component is disabled when the first device enters the low power state.

16. An article comprising a machine-readable storage medium including instructions that if executed by a machine enable the machine to perform a method comprising:

transmitting a request for an idle time window having a first known length from a system component to a target device coupled to the system component via an interconnect; and

committing at least a portion of the system component to an idle state for a time period corresponding to the first known length or a second known length, the second known length shorter than the first known length.

17. The article of claim 16, wherein the method further comprises committing at least the portion to the idle state for the time period corresponding to the second known length after receiving an acknowledgment from the target device, the acknowledgment for the second known length.

18. The article of claim 17, wherein the method further comprises placing an interface of the system component into a low power state for the time period.

19. The article of claim 16, wherein the method further comprises receiving an acknowledgment from the target device for the first known length.

20. The article of claim 19, wherein the method further comprises placing a reference clock and a phase-locked loop of the machine into a low power state responsive to the acknowledgment.

21. The article of claim 16, wherein the method further comprises transmitting the request from a hub interface of the machine to a wireless adapter coupled to the interconnect.

22. The article of claim 21, wherein the method further comprises receiving from the wireless adapter an acknowledgment for the second known length, wherein the wireless adapter is to perform a predetermined activity before the end of the first known length and after the second known length.

23. The article of claim 16, wherein the method further comprises transmitting the request based on a system operating parameter corresponding to a low battery indication.

24. A system comprising:

a first device;

a second device coupled to the first device via an interconnect, wherein the first device is to transmit a message regarding a negotiation for a deterministic idle period for the interconnect based on a priori knowledge of a system operating parameter corresponding to at least one of battery availability or temperature level; and

a dynamic random access memory (DRAM) coupled to the first device and the second device.

25. The system of claim 24, wherein the system comprises a mobile device, the first device comprises a chipset, and the second device comprises a peripheral device.

26. The system of claim 24, wherein the second device is to respond to the message with an acknowledgment for a second deterministic idle period, the second deterministic idle period less than the deterministic idle period.