From: Keith W. <ke...@tu...> - 2002-02-08 04:39:12
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Jose Fonseca wrote: > > I'm in the process of gathering all the interesting information on the > Utah-GLX project to the FAQ. > > Their glossary (http://utah-glx.sourceforge.net/faq.html#AEN364) gives > the definition of PIO, DMA and Pseudo DMA. > > The PIO definition presented there raises no polemics but I don't see > what's different between Pseudo DMA and plain DMA. (It seems that their > concept of plain DMA is in fact MMIO since no reference to MMIO is given > there.) > > Could someone of the 3D gurus enlighten this question? More > specifically, what is "pseudo DMA" and what is the relationship between > DMA and the PIO and MMIO modes? From memory, in pseudo dma filled a buffer with commands (as you would with dma) and then pulled that buffer apart again & sent all the commands via pio. I never really used that myself as I came in after dma was more or less working on the g200, and never had a need to go back. Keith |