Reduced frame refresh rate

• US 9,652,816 B1
• Filed: 09/29/2014
• Issued: 05/16/2017
• Est. Priority Date: 09/29/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Holland, Peter F., Sacchetto, Paolo, Tripathi, Brijesh, de Cesare, Joshua P., Spence, Arthur L., Tann, Christopher P.
• Primary Examiner(s): Chow, Jeffrey
• Application Number:
  US14/500,570
• Time in Patent Office: 960 Days
• CPC Class Codes: G06T 13/00 Animation
• CPC Class Codes: G06T 2200/28 involving image processing hardware
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 5/39 Control of the bit-mapped memory

Abstract

Systems, apparatuses, and methods for adjusting the frame refresh rate used for driving frames to a display. A display pipeline is configured to drive a display using a reduced frame refresh rate in certain scenarios. The reduced frame refresh rate may be specified in frame packets which contain configuration data for processing corresponding frames. The display pipeline may drive idle frames to the display to generate the reduced frame refresh rate. When a touch event is detected, the display pipeline may override the reduced frame refresh rate and instead utilize a standard frame refresh rate until all of the frames corresponding to stored frame packets have been processed.

Claims

1. A display pipeline comprising:

a display backend configured to;

drive a display at a first frame refresh rate when operating in a first mode; and

drive the display at a second frame refresh rate when operating in a second mode, the second frame refresh rate being lower than the first frame refresh rate; and

a display frontend, wherein responsive to detecting a condition for overriding the second frame refresh rate with a third frame refresh rate different from the second frame refresh rate, the display frontend is configured to;

determine a number of frame packets stored in parameter buffer, wherein each frame packet stored in the parameter buffer includes an indication that the second frame rate is to be used for processing the corresponding frame; and

process each of the frame packets at the third frame refresh rate for a number of frames equal to the number of frame packets, wherein the third frame refresh rate at which a given frame is processed is different from the second frame rate specified for the given frame.

2. The display pipeline as recited in claim 1, wherein the display frontend further comprises internal pixel-processing pipelines, and wherein the display frontend is further configured to stop processing frame packets at the third frame refresh rate and begin processing packets at the second frame refresh rate responsive to determining said number of frames equal to the number of frame packets have been processed by the internal pixel-processing pipelines at the third frame refresh rate.

3. The display pipeline as recited in claim 1, wherein the condition for overriding the second frame refresh rate comprises detecting a touch event on the display.

4. The display pipeline as recited in claim 1, wherein the display pipeline is configured to drive the display at the second frame refresh rate by generating one or more idle frames for each active frame.

5. The display pipeline as recited in claim 1, wherein the third frame refresh rate is equal to the first frame refresh rate.

6. The display pipeline as recited in claim 5, wherein the first frame refresh rate is 60 frames per second.

7. A computing system comprising:

a display; and

a display pipeline configured to;

drive a display at a first frame refresh rate when operating in a first mode; and

drive the display at a second frame refresh rate when operating in a second mode, the second frame refresh rate being lower than the first frame refresh rate;

responsive to detecting a condition for overriding the second frame refresh rate with a third frame refresh rate different from the second frame refresh rate;

determine a number of frame packets stored in a parameter buffer, wherein each frame packet stored in the parameter buffer includes an indication that the second frame rate is to be used for processing the corresponding frame; and

process each of the number of frame packets at third frame refresh rate for a number of frames equal to the number of frame packets, wherein the third frame refresh rate at which a given frame to be displayed is processed is different from the second frame rate specified for the given frame.

8. The computing system as recited in claim 7, wherein the display pipeline is further configured to stop processing frame packets at the third frame refresh rate and begin processing packets at the second frame refresh rate responsive to determining said number of frames equal to the number of frame packets have been processed at the third frame refresh rate.

9. The computing system as recited in claim 7, wherein the condition for overriding the second frame refresh rate is detecting a touch event on the display.

10. The computing system as recited in claim 7, wherein the display pipeline is configured to drive the display at the second frame refresh rate by generating one or more idle frames for each active frame.

11. The computing system as recited in claim 7, wherein the third frame refresh rate is equal to the first frame refresh rate.

12. The computing system as recited in claim 11, wherein the third frame refresh rate is 60 frames per second.

13. A method comprising:

driving a display at a first frame refresh rate when operating in a first mode;

driving the display at a second frame refresh rate when operating in a second mode, the second frame refresh rate being lower than the first frame refresh rate;

responsive to detecting a condition for overriding the second frame refresh rate with a third frame refresh rate different from the second frame refresh rate;

determining a number of frame packets to be processed and currently stored in a parameter buffer, wherein each frame packet stored in the parameter buffer includes an indication that the second frame rate is to be used for processing the corresponding frame; and

processing each of the number of frame packets for a frame at the third frame refresh rate for a number of frames equal to the number of frame packets, wherein the third frame refresh rate at which a given frame to be displayed is processed is different from the second frame rate specified for the given frame.

14. The method as recited in claim 13, further comprising stopping processing of frame packets at the third frame refresh rate and beginning processing of frame packets at the second frame refresh rate responsive to determining said number of frames equal to the number of frame packets have been processed at the third frame refresh rate.

15. The method as recited in claim 13, wherein the condition for overriding the second frame refresh rate is detecting a touch event on the display.

16. The method as recited in claim 13, further comprising driving the display at the second frame refresh rate by generating one or more idle frames for each active frame.

17. The method as recited in claim 13, wherein the third frame refresh rate is greater than the second frame refresh rate.