Virtual extended display information data (EDID) in a flat panel controller

• US 7,911,475 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:
  US11/061,151
• Publication Number:
  US 20060082587A1
• Time in Patent Office: 2,223 Days
• Field of Search: 345/699, 345/100, 345/581, 345/543, 345/544, 345/558, 713/320, 704/257
• US Class Current: 345/544
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2370/047 using display data channel standard [DDC] communication
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04

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. In a display controller having a number of data ports each capable of being connected to an appropriate type video source and a processor arranged to process executable instructions and associated data, a method of partitioning a processor memory space to store extended display information data (EDID), comprising:

storing the instructions executed by the processor and associated data in a first portion of the processor memory space; and

storing EDID in a second portion of the processor memory space, wherein the first and the second portions are fully available for access by the data ports even when the display controller and processor are powered off; and

wherein EDID is temporarily stored in a buffer memory and an arbitration circuit provides for execution of EDID read requests and client device read requests within the display controller reading from the processor memory space; and

wherein when the EDID in the buffer memory reaches a low level, the buffer memory is given access to the second portion in order to satisfy pending EDID read requests.

2. A method as recited in claim 1, wherein the allocating the second portion of the processor memory space comprises:

storing analog extended display information data in a first part of the second portion of the processor memory space; and

storing digital extended display information data in a second part of the second portion of the processor memory space.

3. A method as recited in claim 2, wherein at least one of the data ports is an analog data port and at least one of the data ports is a digital data port.

4. A method as recited in claim 3, wherein the at least one analog data port selectively retrieves the analog extended display information data.

5. A method as recited in claim 3, wherein the at least one digital data port selectively retrieves the digital extended display information data.

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

providing power to the processor memory space by way of selected ones of the data ports in a power_off mode operable to be connected to a host device; and

providing power to the processor memory space by an on-board power supply only in a power_on mode.

7. A method as recited in claim 1, wherein the data ports are each connected to the processor memory space by way of I2C compliant data busses.

8. A method as recited in claim 7, further comprising:

arbitrating retrieval of appropriate EDID from the processor memory space by a requesting port and processor memory access requests thereby maintaining I2C compliance.

9. A method as recited in claim 8, wherein a digital port is a DVI port and wherein an analog port is a VGA port.

10. A method as recited in claim 9, 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 processor memory space based upon if the display is analog or digital.

11. A display controller coupled to a display device by way of a display interface and to a host device by way of a number of data ports, comprising:

a processor arranged to process executable instructions and associated data, the processor coupled to a single memory device, external to the display controller, for storing the executable instructions and associated data and extended display identification data (EDID) corresponding to the display device that is fully available for access by the data ports even when the processor and the display controller are powered off;

a buffer memory storage area for temporarily storing EDID read from the single memory device and from where a data port obtains EDID retrieved from the single memory device as instructed by an EDID read request; and

an arbitration circuit for ensuring that the buffer memory storage area has EDID that can be retrieved by the data port by interrupting a client device read request from the processor before the buffer memory storage area is empty, thereby preventing the display controller from having to hold busses connected to the number of data ports.

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

a bridge portion coupling the data ports and the single memory device, wherein the bridge portion and the single memory device are both operable to be powered by the host device such that the host device is operable to access and retrieve the appropriate EDID from the single memory device as needed in a power_down mode.

13. A controller as recited in claim 11, wherein the single memory device is a non-volatile random access memory array.

14. A controller as recited in claim 11, wherein the display controller is a dual port controller suitably arranged to control an analog type display and/or a digital type display.

15. A controller as recited in claim 11, 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.

16. A controller as recited in claim 15, 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.

17. In a display controller having a number of data ports each capable of being connected to an appropriate type video source and a processor arranged to process executable instructions and associated data, computer program product for partitioning a processor memory space so as to store extended display information data (EDID);

comprising;

computer code for storing the instructions executed by the processor and associated data in a first portion of the processor memory space; and

computer code for storing EDID in a second portion of the processor memory space, wherein the first and the second portions are fully available for access by the data ports even when the display controller and processor are powered off; and

wherein EDID is temporarily stored in a buffer memory and an arbitration circuit provides for execution of EDID read requests and client device read requests within the display controller reading from the processor memory space; and

wherein when the EDID in the buffer memory reaches a low level, the buffer memory is given access to the second portion in order to satisfy pending EDID read requests; and

non-transitory computer readable medium for storing the computer code.

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

computer code for partitioning the processor memory space into a first partition and a second partition wherein the first partition is allocated for storage of the executable instructions and associated data and wherein the second partition is allocated for storage of the EDID.

19. Computer program product as recited in claim 18, 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 a requesting port.

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

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

21. Computer program product as recited in claim 20, wherein the first type port is a DVI port and wherein the second type port is a VGA port.

22. Computer program product as recited in claim 21, 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 processor memory space based upon if the display is analog or digital.