On Thu, 4 Apr 2002, Terry Lambert wrote:
> Matthew Jacob wrote:
> > Neither is really applicable here. The actual limits for alpha depend on the
> > platforma and how you implement it. Typically, the bigger alphas have been
> > implemented with a 2GB direct mapped window, and then, if they have it, a S/G
> > map setup for the rest (if any) of memory, which also can include ISA mapping.
>
> Thanks for the clarification. I was confusing BUS_SPACE_MAXSIZE
> with BUS_SPACE_MAXSIZE_24BIT and BUS_SPACE_MAXSIZE_32BIT.
>
> It's probably too late to rename BUS_SPACE_MAXSIZE to something
> like BUS_SPACE_MAXXFER. 8-(.
Yes. If we've understood it at all. There are no documents really describing
it.
>
>
> > The current Alpha 2.4.18 Linux implementation is quite happy to DMA to > 4GB
> > on quite a few alphas.
>
> Ah. Reference code.
>
>
> > BUS_SPACE_MAXSIZE seems to be related to the 'largest xfer you will be allowed
> > to do at one time'- which is wrong because MAXPHYS is larger.
>
> Yeah, I get that now. No need to beat me up, I can take care
> of it myself. 8-) 8-).
No, no.... at least you showed some interest :-)
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