Method of implementing an accelerated graphics port for a multiple memory controller computer system

• US 6,157,398 A
• Filed: 12/30/1997
• Issued: 12/05/2000
• Est. Priority Date: 12/30/1997
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Jeddeloh, Joseph
• Primary Examiner(s): Chauhan, Ulka J.
• Application Number:
  US09/000,517
• Time in Patent Office: 1,071 Days
• Field of Search: 345/501-504, 345/520, 345/521, 345/525, 345/526, 345/507, 345/509, 345/515, 345/513, 345/516, 345/508, 345/511, 345/512, 711/147, 711/153, 711/170, 711/172, 711/173, 711/200, 711/202, 711/203, 711/205, 711/206, 395/280, 395/309, 395/310, 710/112, 710/113, 710/126, 710/128, 710/129, 710/130, 710/131
• US Class Current: 345/532
• CPC Class Codes: G06F 12/0284 Multiple user address space allocation, e.g. using different base addresses interprocessor communication G06F15/163
• CPC Class Codes: G06F 12/0292 using tables or multilevel address translation means G06F12/023 takes precedence; address translation in virtual memory systems G06F12/10
• CPC Class Codes: G06F 12/1081 for peripheral access to main memory, e.g. direct memory access [DMA]
• CPC Class Codes: G09G 2360/121 using a cache memory
• CPC Class Codes: G09G 5/363 Graphics controllers
• CPC Class Codes: G09G 5/39 Control of the bit-mapped memory
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

An architecture for storing, addressing and retrieving graphics data from one of multiple memory controllers. In a first embodiment of the invention, one of the memory controllers having an accelerated graphics port (AGP) includes a set of registers defining a range of addresses handled by the memory controller that are preferably to be used for all AGP transactions. The AGP uses a graphics address remapping table (GART) for mapping memory. The GART includes page table entries having translation information to remap virtual addresses falling within the GART range to their corresponding physical addresses. In a second embodiment of the invention, a plurality of the memory controllers have an AGP, wherein each of the plurality of the memory controllers supplies a set of registers defining a range of addresses that is preferably used for AGP transactions. In a third embodiment of the invention, a plurality of memory controllers implemented on a single chip each contain an AGP and a set of configuration registers identifying a range of addresses that are preferably used for AGP transactions.

Claims

1. A method of manufacturing a multiple memory controller computer comprising:

providing at least two memory controllers for controlling a main memory wherein only a first one of the at least two memory controllers is connected to an accelerated graphics processor, wherein a second one of the at least two memory controllers is adapted for connection to at least one processing unit, and wherein each of the at least two memory controllers is independently and separately connected to a central processing unit (CPU) bus, a peripheral component interface (PCI) bus, and the main memory; and

connecting at least one configuration register to the first one of the at least two memory controllers, wherein said at least one configuration register defines a group of addresses in the main memory that are preferentially used over other addresses for storage of graphics data for accelerated graphics port transactions.

2. The method of claim 1, further comprising the act of controlling a graphical address remapping table having at least one page table entry (PTE) which provides information for a translation of a virtual address to a physical address, wherein the virtual address includes a first portion and a second portion, the first portion corresponding to a PTE in the graphical address remapping table and wherein the second portion and information provided by the PTE are combined to provide the physical address.

3. The method of claim 2, further comprising the act of allocating a virtual page number field to the first portion.

4. The method of claim 2, further comprising the act of allocating an offset field to the second portion.

5. The method of claim 2, further comprising the act of loading said at least one configuration register during boot up of a computer system.

6. The method of claim 5, further comprising the act of defining in a base address register the starting point of memory preferentially used over other addresses for storage of graphics data for accelerated graphics port transactions.

7. The method of claim 5, further comprising the act of setting a boundary address register defining the lowest address of a graphical address relocation table.

8. The method of claim 5, further comprising the act of using a range register in the at least one configuration register to define the amount of memory that is preferentially used over other addresses for storage of graphics data for accelerated graphic port transactions.

9. The method of claim 5, further comprising the act of using an initialization BIOS to load said at least one configuration register.

10. The method of claim 5, further comprising the act of using the operating system API to load said at least one configuration register.

11. The method of claim 1, further comprising the act of manufacturing said at least two memory controllers and a memory on a single semiconductor chip.

12. A method of using a multiple memory controller system comprising:

storing a graphical address remapping table in a main memory on a computer system having at least two memory controllers for controlling a main memory, wherein a selected one of the at least two memory controllers has at least one configuration register that defines a group of addresses in the main memory that are preferentially used over other addresses for storage of graphics data for accelerated graphics port transactions and wherein each of said at least two memory controllers is independently and separately connected to a central processing unit (CPU) bus, a peripheral component interface (PCI) bus, and the main memory;

connecting a graphics accelerator to the selected one of the at least two memory controllers;

storing a graphics address relocation table in a memory connected to the selected one of the at least two memory controllers; and

accessing graphics data through the selected one of the at least two memory controllers.

13. The method of claim 12, wherein the step of storing the graphical address remapping table further comprises storing at least one page table entry (PTE) which provides information for a translation of a virtual address to a physical address, wherein the virtual address includes a first portion and a second portion, the first portion corresponding to a PTE in the graphical address remapping table and wherein the second portion and information provided by the PTE are combined to provide the physical address.

14. The method of claim 13, further comprising the act of storing in the first portion a virtual page number field.

15. The method of claim 13, further comprising the act of storing in the second portion an offset field.

16. The method of claim 13, further comprising the act of loading said at least one configuration register during boot up of a computer system.

17. The method of claim 14, further comprising the act of including in said at least one configuration register a base address of a graphical address remapping table.

18. The method of claim 14, further comprising the act of storing a boundary address in the at least one configuration register to define the lowest address of a graphical address relocation table range.

19. The method of claim 12, further comprising the act of defining the amount of main memory that is preferentially used over other addresses for storage of graphics data for accelerated graphic port transactions in said at least one configuration register.

20. The method of claim 14, further comprising the act of loading said at least one configuration register by an initialization BIOS.

21. The method of claim 14, further comprising the act of loading said at least one configuration register by an operating system API.

22. The method of claim 12, additionally comprising:

sending a memory request from the graphics accelerator to the selected memory controller; and

accessing the main memory through the selected memory controller if the main memory requested by the memory request is within the group of addresses that is preferentially used for accelerated graphics port transactions.

23. A method of using a multiple memory controller system having a main memory, at least two memory controllers for controlling a main memory, and a graphics accelerator that is connected to a selected one of the at least two memory controllers, wherein each of said at least two memory controllers is independently and separately connected to a central processing unit (CPU) bus, a peripheral component interface (PCI) bus, and the main memory, the method comprising:

storing a graphical address remapping table in the main memory, wherein the selected memory controller has a base register and a range register, wherein the base register defines the starting address of main memory that is available preferentially used over other addresses for storage of graphics data for accelerated graphics port transactions, and wherein the range register defines a group of addresses following the address referenced by the base register that are available for accelerated graphics port transactions; and

programming an operating system to preferentially use addresses in the group defined by the base and range registers over other addresses for storage of graphics data when allocating main memory space for accelerated graphics port transactions.

24. The method of claim 23, additionally comprising:

sending a memory request from the graphics accelerator to the selected memory controller; and

accessing the main memory through the selected memory controller if the main memory requested by the memory request is within the group of addresses that is preferentially used for accelerated graphics port transactions.

25. A method of manufacturing a multiple memory controller computer, the method comprising:

providing at least two memory controllers and at least two main memories, wherein a selected one of the at least two memory controllers is connected to one of the at least two main memories, wherein each of the non-selected ones of the at least two memory controllers is connected to another of the at least two main memories, and wherein each of the at least two memory controllers is independently and separately connected to a central processing unit (CPU) bus and a peripheral component interface (PCI) bus;

providing at least one configuration register connected to the selected one of the at least two memory controllers, wherein the at least one configuration register defines a group of addresses that are available for accelerated graphics port transactions; and

configuring the at least two main memories as non-symmetric, with the one of the at least two main memories connected to the selected one of the at least two memory controllers preferentially used for accelerated graphics port transactions.