Dave, When starting out with TTM i did look a little at AGP caching issues and there was an issue with cached memory and speculative pre-fetching that may affect the mapped-cached memory, and that we need to know about but perhaps ignore.
Suppose you bind a page to the AGP aperture, but don't change the kernel linear map caching policy. Then a speculatively prefetching processor may read the memory into its cache and then decide it doesn't want to use it, and actually write it back. Meanwhile the GPU may have changed the contents of the page and that change will be overwritten. Apparently there were big problems with AMD Athlons actually doing this. Linux people claiming it was an Athlon bug and AMD people claiming it was within specs. Anyway, I think they removed this behavior in later Athlon steppings, and I'm not sure there are processors doing this today but we should probably at least keep it in mind and perhaps add a comment at the flag define. /Thomas ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
