System and method to set PME—status bit and wake up the system, and selectively load device driver by searching who set the bit without requiring clock

• US 6,477,655 B1
• Filed: 11/01/1999
• Issued: 11/05/2002
• Est. Priority Date: 12/09/1998
• Status: Expired due to Term

• Current Assignee: CTSI Company Limited
• Original Assignee: GlobespanVirata, Inc. (Synaptics Incorporated)
• Inventors: Delvaux, Marc, Habot, Ronen
• Primary Examiner(s): Lee, Thomas
• Assistant Examiner(s): Patel, Nitin C.
• Application Number:
  US09/431,688
• Time in Patent Office: 1,100 Days
• Field of Search: 713/300-340
• US Class Current: 713/323
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections
• CPC Class Codes: G06F 1/3215 Monitoring of peripheral devices
• CPC Class Codes: G06F 1/3237 by disabling clock generation or distribution
• CPC Class Codes: G06F 1/325 Power saving in peripheral device
• CPC Class Codes: G06F 1/3278 Power saving in modem or I/O interface
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

In general, a system and method for providing PCI power management support without requiring a clock is disclosed. A computer is allowed to reside in a sleep mode and receive a power management event signal from an attached peripheral device in response to an external action request from an external source, thereby waking the computer and initializing device drivers to allow the peripheral device to perform predefined functions. During initiation of the power management system, the system provides a peripheral device with a PME_Status bit. In response to an external event, the peripheral device receives an external action request from the source of the external event. The peripheral device then sets the PME_Status bit and transmits a power management event (PME) signal to a computer operating system. Upon receiving the PME signal, the computer turns back on. The computer operating system then searches all peripheral devices connected to the computer for the set PME_Status bit. Upon finding the source of the PME_Status bit, the computer initializes a device driver, which is related to the peripheral device, thereby allowing the peripheral device to function accordingly and accommodate the external action request.

Claims

1. A system for providing PCI power management support, without requiring a clock, comprising:

a processor based system having an external slot;

a peripheral device connected to said external slot, capable of receiving an external request from an external device, wherein a PME_Status bit is set by said peripheral device in response to said external request;

an operating system, located in said processor based system, capable of waking said processor based system from a sleep mode in response to a power management event (PME) signal received from said peripheral device, and searching said peripheral device for said PME_Status bit; and

a device driver, loaded into said processor based system, capable of being initiated in response to said peripheral device having a set PME_Status bit.

2. The system of claim 1, wherein said sleep mode is further defined by said processor based system turning off power to said peripheral device.

3. The system of claim 1, wherein said sleep mode is further defined by said processor based system deactivating an internal clock.

4. The system of claim 3, wherein said peripheral device is further defined by an external clock located internal to said peripheral device, wherein said external clock is capable of providing a clock signal to said sleeping processor based system so that said device driver is capable of assisting said peripheral device in performing predefined functions.

5. The system of claim 1, further comprising a PME_Enable bit which is capable of determining whether transmission of said PME signal to said processor based system will waken said processor based system.

6. The system of claim 1, wherein said peripheral device is a network interface card.

7. The system of claim 1, wherein said PME signal is transmitted to said processor based system in response to said external request.

8. The system of claim 1, wherein said external slot is a PCI slot.

9. The system of claim 1, wherein said processor based system is a personal computer having a PCI bus.

10. The system of claim 1, wherein said sleep mode is entered into by said processor based system after a predefined time.

11. A method of providing PCI power management support, without requiring a clock, comprising the steps of:

powering up a processor based system;

said processor based system entering into a sleep mode;

setting a PME_Status bit in response to receiving an external event signal;

waking said processor based system in response to said external event signal;

determining a source of said external event signal by searching for a set PME_Status bit; and

initializing a device driver associated with said source of said external event signal.

12. The method of claim 11, wherein said sleep mode is further defined by said processor based system turning off power to external devices attached to said processor based system.

13. The method of claim 12, wherein said external device is a is a network interface card.

14. The method of claim 11, wherein said step of waking said processor based system is further defined by a peripheral device receiving said external event signal and, in response, transmitting a power management event (PME) signal to said processor based system.

15. The method of claim 11, wherein said step of powering up said processor based system is further defined by the step of said processor based system loading said device driver.

16. The method of claim 14, further comprising the step of setting a PME_Enable bit which is capable of determining whether transmission of said PME signal to said processor based system will waken said processor based system.

17. The method of claim 11, wherein said step of entering into a sleep mode is further defined by turning off a clock, internal to said processor based system.

18. The method of claim 17, further comprising the step of providing a clock signal to said sleeping processor based system so that said device driver is capable of being initialized.

19. A system for providing PCI power management support to a processor based system having an external slot, without requiring a clock, comprising:

a means for receiving an external request from an external device, wherein a PME_Status bit is set by said means for receiving in response to said external request;

a means for waking said processor based system from a sleep mode in response to a power management event (PME) signal received from said means for receiving, and searching said means for receiving for said PME_Status bit; and

a device driver, loaded into said processor based system, capable of being initiated in response to said means for receiving having a set PME_Status bit.

20. The system of claim 19, wherein said sleep mode is further defined by said processor based system turning off power to said means for receiving.