SYSTEMS AND METHODS FOR SUSPENDING IDLE DEVICES

• US 20140013137A1
• Filed: 07/09/2012
• Published: 01/09/2014
• Est. Priority Date: 07/09/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Dalal, Anand, Wilson, Daniel B.
• Granted Patent: US 9,477,255 B2
• Time in Patent Office: Days
• US Class Current: 713/323
• CPC Class Codes: G06F 1/00 Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00 architectures of general purpose stored program computers G06F15/76
• CPC Class Codes: G06F 1/32 Means for saving power
• CPC Class Codes: G06F 1/3215 Monitoring of peripheral devices

Abstract

A method for suspending an idle device includes receiving, by a processor, an indication that a device having a communication channel is connected to a host device. The method then includes determining a first timeout value associated with the communication channel and a second timeout value associated with the first device. The first timeout value corresponds to an amount of time allotted for an operation to complete in the communication channel, and the second timeout value corresponds to an amount of time allotted for the device to be designated as idle before the device is suspended. The device is determined to be idle when the operation is pending in the communication channel for an amount of time that is greater than the first timeout value. The device is suspended when the device has been idle for an amount of time that is greater than the second timeout value.

Claims

1. A method, comprising:

receiving, by a processor, an indication that a device having a communication channel is connected to a host device;

determining, by the processor, a first timeout value associated with the communication channel, wherein the first timeout value corresponds to an amount of time allotted for an operation to complete in the communication channel;

determining a second timeout value associated with the first device, wherein the second timeout value corresponds to an amount of time allotted for the device to be designated as idle before the device is suspended;

determining, by the processor, that the device is idle when the operation is pending in the communication channel for an amount of time that is greater than the first timeout value; and

issuing, by the processor, a command to the device when the device has been idle for an amount of time that is greater than the second timeout value, wherein the command is configured to suspend the device.

2. The method of claim 1, wherein determining the first timeout value and the second timeout value comprises retrieving, by the processor, the first timeout value and the second timeout value from a driver associated with the device.

3. The method of claim 1, comprising determining, by the processor, that the device is idle when there is no operation pending in the communication channel.

4. The method of claim 1, wherein suspending the device comprise placing, by the processor, the device in a low-power state such that the device draws a substantially lesser amount of current than in a normal operating state.

5. The method of claim 1, comprising:

determining a third timeout value associated with the device, wherein the third timeout value corresponds to an amount of time allotted for the device to be suspended before the device is disconnected from the host device; and

disconnecting the device when the device has been suspended for an amount of time that is greater than the third timeout value.

6. The method of claim 1, comprising:

determining, by the processor, that the device is no longer idle; and

issuing, by the processor, a resume command to the device when the device is no longer idle, wherein the resume command is configured to enable the device to exit its suspended state.

7. A system comprising:

an external device having one or more communication channels;

a host device coupled to the external device, wherein the host device comprises a processor configured to perform one or more operations using the external device via the one or more communication channels by;

receiving an indication that the external device is connected to the host device;

determining one or more first timeout values associated with the one or more communication channels, respectively, wherein each of the first timeout values corresponds to an amount of time allotted for each respective operation to complete in each respective communication channel;

determining a second timeout value associated with the external device, wherein the second timeout value corresponds to an amount of time allotted for the external device to be designated as idle before the external device is suspended;

determining whether any of the operations using the communication channels are pending;

if at least one of the operations is pending, determining that the external device is idle when the at least one respective operation is pending in its respective communication channel for an amount of time that is greater than its respective first timeout value; and

suspending the external device when the external device has been idle for an amount of time that is greater than the second timeout value.

8. The system of claim 7, wherein the external device comprises a Universal Serial Bus (USB) device.

9. The system of claim 7, wherein the one or more operations comprise one or more read operations, one or more write operations, or any combination thereof.

10. The system of claim 7, wherein the processor is configured to determine the one or more first timeout values retrieving the one or more first timeout values from one or more drivers associated with the one or more communication channels.

11. The system of claim 7, wherein the one or more drivers determines the one or more first timeout values based at least in part on a type of operation being performed in the respective communication channel.

12. The system of claim 7, wherein the processor is configured to manage the external device by determining that the external device is idle when there are no operations pending on the one or more communication channels.

13. The system of claim 7, wherein the processor is configured to manage the external device by determining that the external device is idle when:

the at least one respective operation is pending in its respective communication channel for an amount of time that is greater than its respective first timeout value; and

the remaining communication channels have no operations pending.

14. The system of claim 7, wherein suspending the external device comprises placing the external device in a low-power state such that the external device draws a substantially lesser amount of current than in a normal operating state.

15. The system of claim 7, wherein the external device is a High-Speed Inter-Chip (HSIC) device.

16. The system of claim 15, wherein the processor is configured to manage the external device by:

determining a third timeout value associated with the HSIC device, wherein the third timeout value corresponds to an amount of time allotted for the HSIC device to be suspended before the device is disconnected from the host device; and

disconnecting the HSIC device when the HSIC device has been suspended for an amount of time that is greater than the third timeout value.

17. The system of claim 16, wherein the processor is configured to manage the external device by:

determining that the HSIC device is no longer idle; and

issuing a resume command to the HSIC device when the HSIC device is no longer idle, wherein the resume command is configured to reconnect the HSIC device to the host device.

18. An electronic device comprising:

a processor configured to manage power being consumed by an external device coupled to the electronic device by;

receiving an indication that the external device having a plurality of communication channels is connected to the electronic device;

retrieving a plurality of first timeout values from a plurality of drivers associated with the plurality of communication channels, wherein each first timeout value of the plurality of first timeout values corresponds to an amount of time allotted for a respective operation to complete in a respective communication channel;

retrieving a plurality of second timeout values associated with the first device from the plurality of drivers, wherein each second timeout value of the plurality of second timeout values corresponds to an amount of time allotted for the external device to be designated as idle before the device is suspended;

determining that the external device is idle when;

a respective operation is pending in a respective communication channel for an amount of time that is greater than a respective first timeout value;

or

no operations are pending in at least some of the plurality of communication channels, wherein the at least some of the plurality of communication channels does not include the respective communication channel;

determining a maximum second timeout value in the plurality of second timeout values; and

suspending the external device when the external device has been idle for an amount of time that is greater than the maximum second timeout value.

19. The electronic device of claim 18, wherein the plurality of drivers dynamically determines the plurality of first timeout values based at least in part on periodic traffic characteristics of each of the plurality of communication channels, a plurality of latency times that corresponds to the plurality of communication channels, or any combination thereof.

20. The electronic device of claim 18, wherein the plurality of drivers dynamically determines the plurality of second timeout values based at least in part on an amount of throughput going to the external device.