Re: Athlon/AGP issue update

Oliver Neukum
2002-01-23T19:21:34Z

On Wednesday 23 January 2002 11:18, David S. Miller wrote:
> This means that the fix belongs in the DRM drivers, specifically
> DRM(mmap_dma) should clear the cacheability bits in the
> vma->vm_page_prot at mmap time.

Is that sufficient ? Must the cache be flushed explicitely ?

[..]
> Disabling 4MB translations has zero effect on the problem they say is
> the root all of this. The mappings given to the OpenGL driver to the
> GART memory is still going to be cacheable, thus the problem ought to
> still exist.
>
> As usual, AMD's commentary brings more questions than it answers.

Perhaps speculative writes require an entry in the TLB making it less likely
that they'll happen to 4KB pages.

Regards
Oliver