| 摘要 |
The AGP graphics card queries the system to determine whether the chipset is symmetric or asymmetric. If the chipset is symmetric and other devices can access the graphics address re-mapping table, the graphics aperture is reserved from the system memory. Other devices are denied access to the portion of the system memory reserved for the graphics aperture. The graphics address re-mapping table is then filled to map input addresses in the graphics aperture to identical output addresses. If the chipset is asymmetric and only the Accelerated Graphics Port graphics card can access the graphics address re-mapping table, no system memory is reserved for the graphics aperture, and other devices can access the portion of memory whose addresses are used by the graphics aperture. Then, as the graphics aperture needs additional memory blocks, they are allocated from the system, and input addresses are mapped to the allocated memory blocks within the graphics address re-mapping table.
|
