Method for acquiring extended display identification data (EDID) in a powered down EDID compliant display controller

• US 7,911,473 B2
• Filed: 02/18/2005
• Issued: 03/22/2011
• Est. Priority Date: 10/18/2004
• Status: Active Grant

• Current Assignee: Genesis Microchip Inc. (STMicroelectronics NV)
• Original Assignee: Genesis Microchip Inc. (STMicroelectronics NV)
• Inventors: Noorbakhsh, Ali, Lattanzi, John, Keene, David, Chilukuri, Ram
• Primary Examiner(s): Tung; Kee M
• Assistant Examiner(s): CRAWFORD, JACINTA M
• Application Number:
  US11/061,165
• Publication Number:
  US 20060085627A1
• Time in Patent Office: 2,223 Days
• Field of Search: 345/581, 345/699, 345/100, 713/320, 704/257
• US Class Current: 345/531
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/125 using unified memory architecture [UMA]
• CPC Class Codes: G09G 2370/047 using display data channel standard [DDC] communication
• CPC Class Codes: G09G 5/001 Arbitration of resources in a display system, e.g. control of access to frame buffer by video controller and/or main processor
• CPC Class Codes: G09G 5/363 Graphics controllers

Abstract

A display controller coupled to a display device by way of a display interface and to a host device by way of a data port that includes a processor arranged to process executable instructions and associated data, a single memory device for storing the executable instructions and associated data and EDID corresponding to the display device, and a bridge portion coupling the single memory device to the host device by way of the data port, wherein the bridge portion is always in a powered on state thereby providing access to the single memory device by the host device even when the display controller is in a powered off state such as during a boot up process when the display controller is in the powered off state.

Claims

1. A method for acquiring extended display identification data (EDID) from a single memory device used to concurrently store the EDID and executable instructions and associated data, an EDID compliant multi-port display controller having multiple type ports and a processor, at least one of the ports operable to be coupled to a host device and to receive a request from the host device and operable to receive power from the host device, wherein the single memory device includes at least a first type EDID corresponding to a first type port and a second type EDID corresponding to a second type port, the method comprising:

wherein the display controller is powered off and wherein the processor is powered off and therefore incapable of processing any of the executable instructions and associated data, supplying power to the single memory device by way of the requesting port;

retrieving the EDID stored in the single memory device wherein EDID type corresponds to the port type of the requesting port, and wherein a portion of the EDID is temporarily stored in a buffer memory and when the EDID in the buffer memory reaches a low level, the buffer memory is provided with another portion of EDID in the single memory device to satisfy pending EDID read requests;

passing the retrieved EDID to the requesting port; and

outputting the EDID from the requesting port to the host device.

2. A method as recited in claim 1, wherein when the processor is powered up, the processor processes selected ones of the executable instructions and the associated data as required.

3. A method as recited in claim 1, further comprising:

partitioning the single memory device into a first portion and a second portion wherein the first portion is allocated for storage of the executable instructions and associated data and wherein the second portion is allocated for storage of the EDID.

4. The method as recited in claim 3, further comprising:

further partitioning the second portion allocated for storage of the EDID to a third portion allocated for storage of the first type EDID corresponding to the first type port and the second type EDID corresponding to the second type port.

5. A method as recited in claim 4, wherein the first type port is a DVI port and wherein the second type port is a VGA port.

6. A method as recited in claim 5, further comprising:

determining if a display is a digital display or an analog display;

activating the appropriate port based upon if the display is analog or digital, and

accessing the appropriate portion of the single memory device based upon if the display is analog or digital.

7. A method as recited in claim 1, wherein the display controller is a dual port controller having a first type port and a second type port wherein one of the ports is the requesting port.

8. A multi-port display controller having multiple type ports wherein at least one of the multiple type ports are operable to be coupled to a host device and to receive a request from the host device and operable to receive power from the host device, and wherein the multi-port display controller is coupled to a display device by way of at least one of the multiple type ports, the multi-port display controller comprising:

a processor arranged to process executable instructions and associated data the processor coupled to a single memory device, external to the multi-port display controller, for storing the executable instructions and associated data and extended display identification data (EDID) corresponding to the display device, wherein the single memory device includes at least a first type EDID corresponding to a first type port and a second type EDID corresponding to a second type port, and wherein during boot up of the host device, the processor is powered down and the single memory device receives power and is thereby accessible by the host device without intervention by the processor such that the EDID stored in the single memory device corresponding to the port type of the requesting port is sent to the requesting port.

9. A display controller as recited in claim 8, further comprising:

a third type data port for coupling a bridge portion and the single memory device, wherein the bridge portion and the single memory device are both powered by the host device such that the host device can access and retrieve the appropriate EDID from the single memory device as needed.

10. A controller as recited in claim 8, wherein the display controller is a dual port controller suitably arranged to control an analog type display and/or a digital type display.

11. A controller as recited in claim 10, wherein the portion of the single memory device allocated for storage of the EDID is further partitioned into an analog EDID portion and a digital EDID portion.

12. A controller as recited in claim 11, further comprising:

a display type determinator arranged to determine if the display is an analog or digital display; and

a port activator coupled to the display type determinator arranged to activate an appropriate one of the ports based on the results of the determination of the display type.

13. A non-transitory computer readable medium encoded with computer program product executable by a processor for acquiring extended display identification data (EDID) from a single memory device used to concurrently store the EDID and executable instructions and associated data an EDID compliant multi-port display controller having multiple type ports and the processor, at least one of the ports operable to be coupled to a host device and to receive a request from the host device and operable to receive power from the host device, wherein the single memory device includes at least a first type EDID corresponding to a first type port and a second type EDID corresponding to a second type port, the non-transitory computer-readable medium comprising:

computer code for supplying power to the single memory device by way of the requesting port wherein the display controller is powered off and wherein the processor is powered off and therefore incapable of processing any of the executable instructions and associated data;

computer code for retrieving the EDID stored in the single memory device wherein EDID type corresponds to the port type of the requesting port, and wherein a portion of the EDID is temporarily stored in a buffer memory and when the EDID in the buffer memory reaches a low level, the buffer memory is provided with another portion of EDID in the single memory device to satisfy pending EDID read requests;

computer code for passing the retrieved EDID to the requesting port; and

computer code for outputting the EDID from the requesting port to the host device.

14. Computer program product as recited in claim 13, wherein the processor is arranged to process the executable instructions and associated data as required.

15. Computer program product as recited in claim 14, further comprising:

computer code for partitioning the single memory device into a first portion and a second portion wherein the first portion is allocated for storage of the executable instructions and associated data and wherein the second portion is allocated for storage of the EDID.

16. Computer program product as recited in claim 15, further comprising:

computer code for further partitioning the second portion allocated for storage of the EDID to a third portion allocated for storage of a first type EDID corresponding to the first type port and a second type EDID corresponding to the second type port.

17. Computer program product as recited in claim 16, wherein the first type port is a DVI port and wherein the second type port is a VGA port.

18. Computer program product as recited in claim 17, further comprising:

computer code for determining if a display is a digital display or an analog display;

computer code for activating the appropriate port based upon if the display is analog or digital, and

computer code for accessing the appropriate portion of the single memory device based upon if the display is analog or digital.

19. Computer program product as recited in claim 13, wherein the display controller is a dual port controller having a first type port and a second type port wherein one of the ports is the requesting port.