System and method for dynamic adjustment of an information handling systems graphics bus

1. An information handling system comprising:

plural processing components operable to run one or more applications, the applications generating visual information;

a display operable to present the visual information as an image;

a graphics controller interfaced with the display and operable to convert the visual information to a display format for presentation as the image at the display;

a bus interfacing the processing components and the graphics controller, the bus operable to communicate the visual information from the processing components to the graphics controller over one or more of plural lanes; and

a performance monitor interfaced with the bus and operable to adjust the number of the lanes used to communicate the information by measuring bus utilization, comparing the bus utilization with one or more predetermined thresholds and selectively activating or inactivating predetermined numbers of bus lanes associated with the thresholds based on the comparing.

2. The information handling system of claim 1 wherein the bus comprises a PCI Express bus having plural lanes.

3. The information handling system of claim 2 wherein the PCI Express bus has sixteen lanes.

4. The information handling system of claim 1 wherein the performance monitor comprises:

performance registers operable to track communication across the bus; and

an interrupt module operable to interrupt communication across the bus during a retrain for the adjusted number of lanes.

5. The information handling system of claim 4 wherein the performance registers and interrupt module reside in the graphics controller.

6. The information handling system of claim 1 further comprising:

an internal power source operable to power the processing components; and

an external power source operable to power the processing components and charge the internal power source;

wherein the performance monitor is enabled if power is provided by the internal power source and disabled if power is provided by the external power source.

7. The information handling system of claim 1 wherein the bus utilization thresholds comprise:

a low bandwidth threshold of approximately 250 KB/s or less and associated with a one lane bus activation;

a moderate bandwidth threshold of approximately 250 KB/s to 2 GB/s and associated with an eight lane bus activation; and

a high bandwidth threshold of approximately 2 GB/s or greater and associated with a sixteen lane bus activation.

8. The information handling system of claim 1 further comprising an application interface operable to set predetermined lane activations associated with operation of predetermined applications.

9. A method for communicating information across a bus having plural lane widths, the method comprising:

monitoring bus utilization;

detecting a bus utilization associated with a predetermined of plural thresholds; and

adjusting the number of bus lanes to a number associated with the detected bus utilization.

10. The method of claim 9 wherein the bus comprises a PCI Express bus.

11. The method of claim 10 wherein detecting a bus utilization comprises detecting communication of substantially 2 GB/s of information or greater and adjusting the number of bus lanes comprises retraining the bus to utilize 16 lanes of width.

12. The method of claim 10 wherein detecting a bus utilization comprises detecting communication of substantially between 250 KB/s and 2 GB/s of information and adjusting the number of bus lanes comprises retraining the bus to utilize 8 lanes of width.

13. The method of claim 10 wherein detecting a bus utilization comprises detecting communication of substantially 250 KB/s or less of information and adjusting the number of bus lanes comprises retraining the bus to utilize 1 lane of width.

14. The method of claim 9 further comprising:

adjusting to use all of the bus lanes if power is supplied from an external power source; and

adjusting the number of bus lanes to a number associated with the detected bus utilization if power is supplied from an internal power source.

15. The method of claim 9 wherein adjusting further comprises:

interrupting communication of information across the bus;

retraining the bus for the predetermined number of bus lanes; and

allowing communication of information across the bus when the retraining is complete.

16. The method of claim 9 further comprising communication visual information across the bus to support the presentation of images on a display.

17. A system for communicating information between processing components of an information handling system, the system comprising:

a bus having plural lanes;

a bus controller operable to selectively activate variable numbers of the plural lanes; and

a performance monitor interfaced with the bus and the bus controller, the performance monitor operable to determine the bus utilization and to adjust the number of lanes activated to a number associated with the determined bus utilization.

18. The system of claim 17 wherein the bus comprises a PCI Express bus and the bus controller comprises a PCI Express endpoint switch.

19. The system of claim 17 wherein the plural lanes are sixteen lanes and the performance monitor adjusts between one, eight and sixteen active lanes.

20. The system of claim 17 wherein the performance monitor comprises:

one or more performance registers operable to determine the amount of information communicated across the bus; and

an interrupt module operable to temporarily interrupt the communication of information across the bus during adjustment of the number of lanes.