On Wed, 2005-05-04 at 00:39 +1000, Benjamin Herrenschmidt wrote: > > > Note that with huge VRAM sizes appearing, we also want to make sure that > > > wheverver we put it won't overlap the 32 bits space since CONFIG_MEM_SIZE > > > can be huge nowadays... and if it does, put the GART just _before_ the > > > framebuffer instead. Again, this is all cards space, not bus view, so that > > > shouldn't matter where we put these things. > > > > Another constraint is that the GART doesn't overlap with the bus address > > range of system RAM. > > Do we still care about that ? Do we ever do DMA from the card to system > RAM outside of the AGP context ?
Yes, e.g. for video capture (hence it's doubly surprising that the framebuffer location would be hardcoded to 0 for r300 ;). We should also use non-GART for the ring read pointer and scratch register writeback. > I think a good strategy is to try to put the AGP aperture after the > video RAM, and if that doesn't fit, just before. That would keep us > "high enough" in most cases to avoid system RAM, but we can't guarantee > 100% here. If a conflict can't be avoided, we could fail gracefully upfront (suggesting to make the GART aperture smaller, ...) instead of risking subtle breakage? -- Earthling Michel DÃnzer | Debian (powerpc), X and DRI developer Libre software enthusiast | http://svcs.affero.net/rm.php?r=daenzer ------------------------------------------------------- This SF.Net email is sponsored by: NEC IT Guy Games. Get your fingers limbered up and give it your best shot. 4 great events, 4 opportunities to win big! Highest score wins.NEC IT Guy Games. Play to win an NEC 61 plasma display. Visit http://www.necitguy.com/?r -- _______________________________________________ Dri-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/dri-devel
