Re: [Dri-devel] 3d glossary

[Stephen C. T. <sc...@re...>]

Hi,

On Thu, Dec 21, 2000 at 11:45:47AM -0500, Rik Faith wrote:
> 
> AGP: Accelerated Graphics Port.  A dedicated high-speed bus that allows
> the graphics controller to move large amoumts of data directly from
> system memory.  Uses a Graphics Address Re-Mapping Table (GART) to map
> discontiguous pages of physical memory into a contiguous physical
> address range.  This allows the graphics card and the kernel to access
> the (discontiguous) memory using contiguous addresses.

I'm not sure if AGP requires that the implementation supports GART
mapping for accesses from the CPU.  As far as I know, the GART is only
_required_ to be active for AGP bus cycles: whether or not PCI or CPU
accesses go through the GART is implementation-defined.

Can the CPU really rely on GART memory appearing virtually contiguous?

--Stephen