On Tue, Feb 19, 2002 at 03:22:09PM -0800,
David Griffiths <dgriffiths@boats.com> wrote:
>
> I've heard that there is a kernal bug with the Athalon (Microsoft has a
> registry patch for it). Maybe only with nVidia graphics cards? Couldn't find
> a reference.
This got press on /. and other places. Some memory addresses used by AGP
cards is marked as cacheable when large (1MB?) segments are used to map
some of the kernel address space. This is incorrect.
When data in that area of memory is read with some Athlon processors
the cached data is written back to memory even though the data wasn't
changed. However, by that time the data may have already been changed
by the AGP card, which is a problem.