US5748968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Requesting device capable of canceling its memory access requests upon detecting other specific requesting devices simultaneously asserting access requests
Assignee: Nvidia Corp
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Filing: 1996-01-05
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Granted: 1998-05-05
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Expires: 2016-01-05
Abstract
Abstract A memory bandwidth allocation scheme in a computer system having a unified memory architecture. When a first device requesting access to a resource detects that two higher priority devices are also requesting access to the same resource, the first device shuts itself down. Accordingly, the first device deactivates its access request signals and clears its buffers. Then, the first device reactivates itself when it receives a graphics VSYNC signal. This allocation scheme ensures that the arbiter will not get stuck in a loop serving only high priority requests and not serving lower priority requests.
Inventors
- 👤 Robert Marshall Nally
- 👤 Pete Edward Nelsen
- 👤 Douglas Hamilton
- 👤 Douglas Michael Berk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:54
CPC Classifications
G; G09; G09G; G09G5/00; G09G5/001; G06; G06F; G06F13/00; G06F13/14; G06F13/16; G06F13/18; G09G2360/00; G09G2360/12; G09G2360/125; G09G2360/128; G09G5/36; G09G5/363
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
98 words
A requesting device for monitoring an arbitration controller that arbitrates access to a resource in a computer system having the requesting device and a plurality of other requesting devices, comprising: circuitry for detecting when the requesting device and particular ones of the other requesting devices are asserting access requests; circuitry for canceling the access requests of the requesting device when the circuitry for detecting detects that the requesting device and the particular ones of the other requesting devices are asserting access requests; and circuitry for regenerating the access requests from the requesting device when a signal goes active.
Claim 2
Dependent Claim
98 words
A requesting device for monitoring an arbitration controller that arbitrates access to a resource in a computer system having the requesting device and a plurality of other requesting devices, comprising: circuitry for detecting when the requesting device and particular ones of the other requesting devices are asserting access requests; circuitry for canceling the access requests of the requesting device when the circuitry for detecting detects that the requesting device and the particular ones of the other requesting devices are asserting access requests; and circuitry for regenerating the access requests from the requesting device when a signal goes active.
Claim 3
Dependent Claim
14 words
The requesting device of claim 1, wherein the signal comprises a graphics VSYNC signal.
Claim 4
Dependent Claim
13 words
The requesting device of claim 1, wherein each requesting device comprises a FIFO.
Claim 5
Dependent Claim
43 words
The requesting device of claim 1, wherein the other requesting devices are capable of asserting HWM and LWM access requests and the circuitry for detecting comprises: circuitry for detecting when the particular ones of the other requesting devices are asserting LWM access requests.
Claim 6
Dependent Claim
12 words
The requesting device of claim 1, wherein the resource is a memory.
Claim 7
Dependent Claim
12 words
The requesting device of claim 5, wherein the memory is an SDRAM.
Claim 8
Dependent Claim
30 words
The requesting device of claim 1, wherein the circuitry for canceling the access requests of the requesting device further comprises: circuitry for clearing a FIFO associated with the requesting device.
Claim 9
Independent Claim
70 words
A method of arbitrating access to a resource in a computer system having a plurality of requesting devices capable of asserting access requests, comprising: detecting when particular ones of the requesting devices are asserting access requests; canceling the access requests of a requesting device when the particular ones of the requesting devices are asserting access requests; and regenerating the access requests from the requesting device when a signal goes active.
Claim 10
Independent Claim
70 words
A method of arbitrating access to a resource in a computer system having a plurality of requesting devices capable of asserting access requests, comprising: detecting when particular ones of the requesting devices are asserting access requests; canceling the access requests of a requesting device when the particular ones of the requesting devices are asserting access requests; and regenerating the access requests from the requesting device when a signal goes active.
Claim 11
Dependent Claim
13 words
The method of claim 8, wherein the signal comprises a graphics VSYNC signal.
Claim 12
Dependent Claim
12 words
The method of claim 8, wherein each requesting device comprises a FIFO.
Claim 13
Dependent Claim
42 words
The method of claim 8, wherein the plurality of requesting devices are capable of asserting HWM and LWM access requests and the detecting step comprises the step of: detecting when the particular ones of the requesting devices are asserting LWM access requests.
Claim 14
Dependent Claim
22 words
The method of claim 8, wherein the canceling step further comprises the step of: clearing a FIFO associated with the requesting device.
Claim 15
Dependent Claim
11 words
The method of claim 8, wherein the resource is a memory.
Claim 16
Dependent Claim
11 words
The method of claim 13, wherein the memory is an SDRAM.
Claim 17
Dependent Claim
94 words
A computer system having a CPU, a resource connected to the CPU, a plurality of requesting devices capable of asserting resource access requests, and arbitration means for arbitrating among the resources access requests, comprising: means for detecting when particular ones of the requesting devices are asserting resource access requests; means for canceling the access requests of a requesting device when the means for detecting detects that the particular ones of the requesting devices are asserting resource access requests; and means for regenerating the access requests from the requesting device when a signal is received.
Claim 18
Dependent Claim
94 words
A computer system having a CPU, a resource connected to the CPU, a plurality of requesting devices capable of asserting resource access requests, and arbitration means for arbitrating among the resources access requests, comprising: means for detecting when particular ones of the requesting devices are asserting resource access requests; means for canceling the access requests of a requesting device when the means for detecting detects that the particular ones of the requesting devices are asserting resource access requests; and means for regenerating the access requests from the requesting device when a signal is received.
Claim 19
Dependent Claim
14 words
The computer system of claim 15, wherein the signal comprises a graphics VSYNC signal.
Claim 20
Dependent Claim
13 words
The computer system of claim 15, wherein each requesting device comprises a FIFO.
Claim 21
Dependent Claim
45 words
The computer system of claim 15, wherein the plurality of requesting devices are capable of asserting HWM and LWM resource access requests and the means for detecting comprises: means for detecting when the particular ones of the requesting devices are asserting LWM resource access requests.
Claim 22
Dependent Claim
30 words
The computer system of claim 15, wherein the means for canceling the access requests of a requesting device further comprises: means for clearing a FIFO associated with the requesting device.
Claim 23
Dependent Claim
12 words
The computer system of claim 15, wherein the resource is a memory.
Claim 24
Dependent Claim
12 words
The computer system of claim 20, wherein the memory is an SDRAM.
Claim 25
Independent Claim
74 words
A method for dynamic allocation of a resource in a computer system among a plurality of requesting devices capable of asserting access requests, comprising the steps of: (a) detecting when an arbitration controller is servicing only selected requesting devices; (b) responsive to step (a), canceling access requests of a predetermined requesting device among said selected requesting devices thereof; and (c) causing the predetermined requesting device to regenerate access requests when a signal goes active.
Claim 26
Independent Claim
74 words
A method for dynamic allocation of a resource in a computer system among a plurality of requesting devices capable of asserting access requests, comprising the steps of: (a) detecting when an arbitration controller is servicing only selected requesting devices; (b) responsive to step (a), canceling access requests of a predetermined requesting device among said selected requesting devices thereof; and (c) causing the predetermined requesting device to regenerate access requests when a signal goes active.
Claim 27
Dependent Claim
13 words
The method of claim 22, wherein the signal comprises a graphics VSYNC signal.
Claim 28
Dependent Claim
15 words
The method of claim 22, wherein each of the selected requesting devices includes a FIFO.
Claim 29
Dependent Claim
42 words
The method of claim 22, wherein the plurality of requesting devices are capable of asserting critical and non-critical access requests and step (a) includes the substep of: detecting when the particular ones of the selected requesting devices are asserting critical access requests.
Claim 30
Dependent Claim
15 words
The method of claim 25, wherein the critical access requests include a LWM access request.
Claim 31
Dependent Claim
15 words
The method of claim 25, wherein the non-critical access requests include a HWM access request.
Claim 32
Dependent Claim
23 words
The method of claim 22, wherein the canceling step further includes the substep of: clearing a FIFO associated with the predetermined requesting device.
Claim 33
Dependent Claim
11 words
The method of claim 22, wherein the resource is a memory.
Claim 34
Dependent Claim
11 words
The method of claim 29, wherein the memory is an SDRAM.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-05-04 | 2001-11-03 | 2002-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-04 | 2005-11-03 | 2006-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-04 | 2009-11-03 | 2010-05-05 | $7700.00 | Window Closed / Lapsed |