On Mon, Jun 10, 2002 at 07:37:19PM +0100, José Fonseca wrote: > On 2002.06.10 18:32 Ville Syrjälä wrote: > > Here's my understanding of the situation. Someone more enlightened should > > correct me if I'm wrong. > > > > On Mon, Jun 10, 2002 at 04:22:11PM +0000, Gareth Knight wrote: > > > I am interested in adding DRI support for an Algorithmics P6064 mips > > > development board. I already have the standard X server working OK > > > > > > ... > > > > This might be nasty as the card doesn't do scatter-gather DMA. You'd need > > a physically contiguous chunk of memory which the Linux kernel can't > > guarantee. I'm not sure how much memory the DMA buffers require. Putting > > textures to PCI memory might be useless speedwise, but maybe the driver > > would be cleaner as the card would fetch the textures by itself so the > > driver wouldn't have to swap them constatly. utah-glx required the user > > to permanently steal memory with the kernel mem= option. This approach > > would also mess up mtrr setup. I can think of one nice advantage: It > > would > > work on every card from G200 to G550. People with AGP cards could also > > test it so you'd have "lots" of testers. > > I'm not sure about the Matrox design, but in the absence of AGP and PCI > scatter-gather DMA, generally a card will only allow to have textures on > the onboard memory. This it's what happens on the 3DFX, Gamma, and Mach64 > drivers when handling the PCI versions. This is also why you don't find > PCI cards with so little memory as the AGP counterparts - they can't rely > on the system memory to fill in the rest..
Well I'm not sure but the the DSTORG (destination origin) register has one bit to specify the location (card memory or system memory) and one bit for access type (PCI or AGP). DSTORG must be initialized for all graphics operations. So I'm thinking the card should be able operate on all types of memory and even back and depth buffers can reside in system memory. I think utah-glx did this even before AGP support was added. -- Ville Syrjälä [EMAIL PROTECTED] http://www.sci.fi/~syrjala/ _______________________________________________________________ Sponsored by: ThinkGeek at http://www.ThinkGeek.com/ _______________________________________________ Dri-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/dri-devel
