Low power mode for device power management

• US 20040243858A1
• Filed: 05/29/2003
• Published: 12/02/2004
• Est. Priority Date: 05/29/2003
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: Walker, Andrew A., Dennis, Lowell Browning
• Granted Patent: US 7,437,575 B2
• Time in Patent Office: Days
• US Class Current: 713/300
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode

Abstract

An information handling system having PCI devices which comply with the Power Management Interface Specification have a low power mode that may be used to put Power Management Capability devices into a low power state when the information handling system enters into S4 or S5. A firmware or software low power mode program, retained in non-volatile memory of the information handling system, recognizes when the information handling system is entering S4 or S5. The low power mode program may clear the Power Management Event Enable or not in each of the Power Management Capable devices when the information handling system enters into S4 or S5.

Claims

1. An information handling system having a low power mode, said system comprising:

information handling equipment having at least one system low power mode;

at least one device of said information handling equipment having low power capability, said at least one device having a low power enable wherein when the low power enable is in a first logic state said at least one device draws reduced power when said information handling equipment is in the at least one system low power mode; and

a non-volatile memory in said information handling equipment, said non-volatile memory having a low power mode bit, wherein when the low power mode bit is at a first logic level the low power enable is in the first logic state.

2. The information handling system according to claim 1, wherein the first logic level is a logic low.

3. The information handling system according to claim 1, wherein the first logic level is a logic high.

4. The information handling system according to claim 1, wherein the first logic state is a logic low.

5. The information handling system according to claim 1, wherein the first logic state is a logic high.

6. The information handling system according to claim 1, wherein said at least one device is PCI Bus Power Management Interface Specification compliant.

7. The information handling system according to claim 6, wherein the low power enable is a PME_En bit.

8. The information handling system according to claim 6, wherein said at least one device is a multi-function PCI device.

9. The information handling system according to claim 1, wherein said non-volatile memory is selected from the group consisting of battery backed-up complementary metal oxide silicon (CMOS) memory, non-volatile random access memory (NVRAM) and FLASH memory.

10. The information handling system according to claim 1, wherein said non-volatile memory is part of said information handling equipment'"'"'s basic input/output system (BIOS).

11. The information handling system according to claim 1, wherein the at least one system low power mode is selected from the group consisting of Advanced Configuration and Power Interface (ACPI) specification S4 and S5 states.

12. The information handling system according to claim 1, wherein said information handling equipment is selected from the group consisting of computer, personal computer workstation, portable computer, computer server, print server, network router, network hub, network switch, storage area network disk array, RAID disk system and telecommunications switch.

13. A method for reducing power consumption in an information handling system, said method comprising the steps of:

a) determining an occurrence of a system power mode change;

b) determining whether a low power mode is enabled after the occurrence of the system power mode change, wherein

i) if the low power mode is not enabled, then go to step e), and

ii) if the low power mode is enabled, then go to step c);

c) determining whether a device is on a bus, wherein

i) if there is no device on the bus, then go to step e), and

ii) if the device is present, then go to step d);

d) determining whether the device supports Power Management Capability, wherein

i) if the device does not support Power Management Capability, then go to step e), and

ii) if the device supports Power Management Capability, then clear Power Management Event Enable; and

e) end.

14. The method according to claim 13, wherein step e) further comprises the step of returning to step a).

15. The method according to claim 13, after step d) further comprising the steps of:

da) determining whether the device is a multi-function device, wherein

i) if the device is not a multi-function device, then go to step db), and

ii) if the device is a multi-function device, then go to step d);

db) determining whether another device is on the bus, wherein

i) if there is no other device on the bus, then go to step e), and

ii) if another device is present, then go to step d).

16. The method according to claim 13, after step d) further comprising the steps of:

daa) determining whether another bus is present, wherein

i) if no other bus is present, then go to step e), and

ii) if another bus is present, then go to step c).

17. The method according to claim 13, after step d) further comprising the steps of:

da) determining whether the device is a multi-function device, wherein

i) if the device is not a multi-function device, then go to step db), and

ii) if the device is a multi-function device, then go to step d);

db) determining whether another device is on the bus, wherein

i) if there is no other device on the bus, then go to step dc), and

ii) if another device is present, then go to step d);

dc) determining whether another bus is present, wherein

i) if no other bus is present, then go to step e), and

ii) if another bus is present, then go to step c).

18. A method for reducing power consumption in an information handling system, said method comprising the steps of:

a) determining an occurrence of a system power mode change;

b) determining whether a low power mode is enabled after the occurrence of the system power mode change, wherein

i) if the low power mode is not enabled, then go to step h), and

ii) if the low power mode is enabled, then go to step c);

c) determining whether a device is on a bus, wherein

i) if there is no device on the bus, then go to step h), and

ii) if the device is present, then go to step d);

d) determining whether the device supports Power Management Capability, wherein

i) if the device does not support Power Management Capability, then go to step h), and

ii) if the device supports Power Management Capability, then clear device Power Management Event Enable;

e) determining whether the device is a multi-function device, wherein

i) if the device is not a multi-function device, then go to step f), and

ii) if the device is a multi-function device, then go to step d);

f) determining whether another device is on the bus, wherein

i) if there is no other device on the bus, then go to step g), and

ii) if another device is present, then go to step d);

g) determining whether another bus is present, wherein

i) if no other bus is present, then go to step h), and

ii) if another bus is present, then go to step c); and

h) end.

19. The method according to claim 18, wherein step h) further comprises the step of returning to step a).

20. A method for reducing power consumption in an information handling system, said method comprising the steps of:

a) determining a change in a system power mode;

b) determining whether a device is on a bus, wherein

i) if there is no device on the bus, then go to step g), and

ii) if the device is present, then go to step c);

c) determining whether the device supports Power Management Capability, wherein

i) if the device does not support Power Management Capability, then go to step g), and

ii) if the device supports Power Management Capability, then clear device Power Management Event Enable;

d) determining whether the device is a multi-function device, wherein

i) if the device is not a multi-function device, then go to step e), and

ii) if the device is a multi-function device, then go to step c);

e) determining whether another device is on the bus, wherein

i) if there is no other device on the bus, then go to step f), and

ii) if another device is present, then go to step c);

f) determining whether another bus is present, wherein

i) if no other bus is present, then go to step g), and

ii) if another bus is present, then go to step b); and

h) end.

21. The method according to claim 20, wherein the system power mode is selected from the group consisting of Advanced Configuration and Power Interface (ACPI) specification S4 and S5 states.

22. A method for reducing power consumption in an information handling system, said method comprising the steps of:

a) determining an occurrence of a system power mode change;

b) determining whether a low power mode is enabled after the occurrence of the system power mode change, wherein

i) if the low power mode is not enabled, then go to step e), and

ii) if the low power mode is enabled, then go to step c);

c) determining whether a device is present, wherein

i) if no device is present, then go to step e), and

ii) if the device is present, then go to step d);

d) determining whether the device supports low power capability, wherein

i) if the device does not support low power capability, then go to step e), and

ii) if the device supports low power capability, then set the device to a low power mode; and

e) end.

23. The method according to claim 22, wherein step e) further comprises the step of returning to step a).

24. The method according to claim 22, wherein steps c) and d) are repeated until the presence of all devices are determined, whether these devices support low power capability, and, if they support low power capability, then are set to the low power mode.