On Tue, 2005-05-10 at 14:59 -0700, Ian Romanick wrote:
I've started working to get PCI MGA cards, the PCI G450 specifically, working with DRI. My initial goal is to just get it working with crummy performance, then improve it by adding support for IOMMUs (to simulate AGP texturing) on systems like pSeries and AMD64 that have them.
I've started by digging through the DRI init process in the X.org MGA DDX. As near as I can tell, the driver uses AGP memory for four things. To make the PCI cards work, I'll need to make it do without AGP for these things.
Note that most of these issues can be more easily dealt with if you assume an iommu. What you basically want to do is create a virtual mapping, build an sglist, and have the iommu coalesce that into a single PCI DMA mapping.
Right. I want to try to walk before I run, though. Right now the card is in a PPC32 box anyway, so I don't have an IOMMU. Physical access to the PPC32 box is much easier for me than to the pSeries, so I'm going to /try/ and keep it there as long as I can. Besides, a Mac reboots a lot faster than a p275. ;)
Unfortunately, the current iommu API doesn't really have a way to enforce the iommu driver to create a single mapping. It will happen most of the time, but can't be enforced. We may have to add something to the DMA APIs to add this ability, or do a quick hack in the meantime as a proof of concept. I could do something for pSeries if you need that.
Okay. I /will/ need that at some point, but that point is still a ways off. I'll let you know when it gets closer. Thanks. :)
------------------------------------------------------- This SF.Net email is sponsored by Oracle Space Sweepstakes Want to be the first software developer in space? Enter now for the Oracle Space Sweepstakes! http://ads.osdn.com/?ad_id=7393&alloc_id=16281&op=click -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
