Hi Garrett, Garrett D'Amore pÃÅ¡e v po 01. 09. 2008 v 16:52 -0700: > Steven Stallion wrote: > > Ouch, good catch! I just double checked the spec, and you are completely > > right, even though LAS powers high on the 8029, it must be set to zero > > effectively forcing you to use the 16-bit DMA configuration. > > > > Looks like I'll have to rework DMA ;) > > > > If the primary target for this is for emulated devices (i.e. QEMU, > Parallels) it may be simpler to skip DMA altogether. (It isn't clear to > me that emulated DMA offers a performance win in those situations -- if > it does, I'd expect it to be quite minimal. But then again, I'm not > sure how painful the logic behind emulated PIO is either.) >
DMA improves usually performance significantly in emulators in comparison to PIO (you don't need to process PIO so frequently in emulator in such cases, processing every PIO takes a lot of cycles, where DMA not). Best regards, Milan
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