On 3/22/07, Michel Dänzer <[EMAIL PROTECTED]> wrote: > On Wed, 2007-03-21 at 00:58 +0300, malc wrote: > > On Tue, 20 Mar 2007, Michel D?nzer wrote: > > > > > On Thu, 2007-03-15 at 21:36 +0300, malc wrote: > > >> > > >> Apparently the problem is that pages obtained by the call to > > >> get_user_pages admit caching, so adding flush_dcache_range upon > > >> dequeuing buffer in the device driver removes the artifacts. > > >> > > >> Even with this i still get roughly a 3x speedup compared to > > >> grab to some buffer then copy to gart with memcpy. > > >> > > >> However i believe things can be improved: > > >> 1. call glXGetMemoryOffsetMESA > > >> 2. tell the driver to grab into "special" memory with this offset > > >> > > >> This should avoid the need of having to mess with get_user_pages and > > >> caching altogether. > > >> > > >> Question is though, is this possible at all? > > > > > > Possibly. In fact, it should be easy with a traditional AGP bridge which > > > provides a physically linear view of the aperture to the CPU. > > > Unfortunately, that's not the case with Apple UniNorth bridges, so is > > > this on a Mac or a different PowerPC machine such as a Pegasos? If the > > > former I suspect you may have to hook into the DRM or agpgart to get at > > > the pages backing the AGP mapping. > > > > Thanks for the answer, i had a feeling of being either completely offtopic > > or a subject to overzelous spam filtering. > > > > It's a Mac (mini) with UniNorth. I don't mind at all having to deal with > > non linear mappings, current code is already in this situation. > > So I think basically you need to determine the mapping of the allocated > memory to physical pages and tell the grabber to write to those pages. > > > Unfortunately my knowlege of AGP/GARTs/appertures is virtually non-existent, > > i was wondering if there's a document that describes the basic concepts to > > the layman? > > I don't know of one, but someone on the list might. >
wikipedia has some basic info: http://en.wikipedia.org/wiki/IOMMU Alex ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Mesa3d-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/mesa3d-dev
