METHOD OF AND APPARATUS FOR CONTROLLING FRAME BUFFER OPERATIONS

• US 20140354664A1
• Filed: 06/03/2013
• Published: 12/04/2014
• Est. Priority Date: 06/03/2013
• Status: Active Grant

• Current Assignee: Arm Ltd. (United Kingdom) (SoftBank Group Corp.)
• Original Assignee: Arm Ltd. (United Kingdom) (SoftBank Group Corp.)
• Inventors: Brown, David
• Granted Patent: US 9,640,148 B2
• Time in Patent Office: Days
• US Class Current: 345/545
• CPC Class Codes: G06F 3/1415 with means for detecting differences between the image stored in the host and the images displayed on the displays
• CPC Class Codes: G06T 1/60 Memory management
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2360/122 Tiling
• CPC Class Codes: G09G 5/363 Graphics controllers
• CPC Class Codes: G09G 5/393 Arrangements for updating the contents of the bit-mapped memory
• CPC Class Codes: G09G 5/395 Arrangements specially adapted for transferring the contents of the bit-mapped memory to the screen G09G5/399 takes precedence

Abstract

A data processing system comprises a host processor and a graphics processor that renders frames to be output and writes those frames to a frame buffer.

When a new frame is to be generated and written to the frame buffer, the host processor determines, for a set of plural sub-regions that the frame has been divided into, which of those sub-regions could have changed from the frame previously used for the frame buffer 30 and generates information indicating which sub-regions should be rendered to generate the new frame on the basis of the determination 31.

The information indicating which sub-regions should be rendered to generate the frame is provided to the graphics processor 32 and the graphics processor uses the provided sub-region information to render only the indicated sub-regions 33.

Claims

1. A method of operating a data processing system that comprises a host processor and a graphics processor that in response to commands and data received from the host processor, renders frames to be output and writes those frames to a frame buffer, the method comprising:

when a new frame is to be generated and written to the frame buffer;

determining, for a set of plural sub-regions that the frame has been divided into, which of those sub-regions could have changed from the frame previously-used for the frame buffer;

generating information indicating for the set of plural sub-regions that the frame has been divided into, which of those sub-regions should be rendered to generate the new frame on the basis of the determination; and

providing to the graphics processor information indicating, for the set of plural sub-regions that the frame has been divided into, which of those sub-regions should be rendered to generate the frame; and

the graphics processor using the provided sub-region information to determine those sub-regions in the frame that it should render, rendering those sub-regions, and writing the so-rendered sub-regions to the frame buffer.

2. The method of claim 1, wherein each frame sub-region corresponds to a rendering tile that the graphics processor that is rendering the frame produces as its rendering output.

3. The method of claim 1, wherein each frame sub-region corresponds to a set of plural rendering tiles that the graphics processor that is rendering the frame produces as its rendering output.

4. The method of claim 1, comprising determining which sub-regions could have changed from the frame previously used for the frame buffer from a list of dirty regions provided by the host processor.

5. The method of claim 1, comprising determining which sub-regions could have changed from the frame previously used for the frame buffer by converting a screen-space area indication of changed parts of a frame to sub-region indications within the frame.

6. The method of claim 1, comprising determining which sub-regions could have changed from the frame previously used for the frame buffer by comparing respective sub-regions in the frames to determine which sub-regions have changed between the frames.

7. The method of claim 6, wherein the comparison process comprises comparing signatures representative of the content of the respective frame sub-regions.

8. The method of claim 1, wherein the information indicating which sub-regions of the set of sub-regions that the frame has been divided into should be rendered comprises a bitmap with each bit representing a respective sub-region in the frame.

9. The method of claim 1, wherein the host processor determines which of the sub-regions could have changed from the frame previously used for the frame buffer, and generates the information indicating which sub-regions should be rendered to generate the new frame.

10. The method of claim 1, wherein the graphics processor determines which of the sub-regions could have changed from the frame previously used for the frame buffer, and generates the information indicating which sub-regions should be rendered to generate the new frame.

11. A data processing system comprising:

a host processor;

a graphics processor that in response to commands and data received from the host processor, renders frames to be output and writes those frames to a frame buffer; and

a frame buffer that stores output frames generated by the graphics processor;

wherein the data processing system is configured to;

when a new frame is to be generated and written to the frame buffer;

determine, for a set of plural sub-regions that the frame has been divided into, which of those sub-regions could have changed from the frame previously used for the frame buffer;

generate information indicating for the set of plural sub-regions that the frame has been divided into, which of those sub-regions should be rendered to generate the new frame on the basis of the determination; and

provide to the graphics processor the information indicating, for the set of plural sub-regions that the frame has been divided into, which of those sub-regions should be rendered to generate the frame; and

the graphics processor is configured to use the provided sub-region information to determine those sub-regions in the frame that it should render, render those sub-regions, and to write the so-rendered sub-regions to the frame buffer.

12. The system of claim 11, wherein each frame sub-region corresponds to a rendering tile that the graphics processor that is rendering the frame produces as its rendering output.

13. The system of claim 11, wherein each frame sub-region corresponds to a set of plural rendering tiles that the graphics processor that is rendering the frame produces as its rendering output.

14. The system of claim 11, wherein the sub-regions that could have changed from the frame previously used for the frame buffer are determined from a list of dirty regions provided by the host processor.

15. The system of claim 11, wherein the sub-regions that could have changed from the frame previously used for the frame buffer are determined by converting a screen-space area indication of changed parts of a frame to sub-region indications within the frame.

16. The system of claim 11, wherein the sub-regions that could have changed from the frame previously used for the frame buffer are determined by comparing respective sub-regions in the frames to determine which sub-regions have changed between the frames.

17. The system of claim 16, wherein the comparison process comprises comparing signatures representative of the content of the respective frame sub-regions.

18. The system of claim 11, wherein the information indicating which sub-regions of the set of sub-regions that the frame has been divided into should be rendered comprises a bitmap with each bit representing a respective sub-region in the frame.

19. The system of claim 11, wherein the host processor determines which of the sub-regions could have changed from the frame previously used for the frame buffer, and generates the information indicating which sub-regions should be rendered to generate the new frame.

20. The system of claim 11, wherein the graphics processor determines which of the sub-regions could have changed from the frame previously used for the frame buffer, and generates the information indicating which sub-regions should be rendered to generate the new frame.

21. A computer readable storage medium storing computer software code which when executing on a processor performs a method of operating a data processing system that comprises a host processor and a graphics processor that in response to commands and data received from the host processor, renders frames to be output and writes those frames to a frame buffer, the method comprising:

when a new frame is to be generated and written to the frame buffer;

determining, for a set of plural sub-regions that the frame has been divided into, which of those sub-regions could have changed from the frame previously-used for the frame buffer;

generating information indicating for the set of plural sub-regions that the frame has been divided into, which of those sub-regions should be rendered to generate the new frame on the basis of the determination; and

providing to the graphics processor information indicating, for the set of plural sub-regions that the frame has been divided into, which of those sub-regions should be rendered to generate the frame; and

the graphics processor using the provided sub-region information to determine those sub-regions in the frame that it should render, rendering those sub-regions, and writing the so-rendered sub-regions to the frame buffer.