Re: (reposting) how to get DMA'able memory within 4GB on 64-bit m

Jeff Garzik
2001-07-07T12:18:16Z

Alan Cox wrote:
>
> > > that the expected lifespan for 32 bit systems is now less than 3 years, so
> > > elaborate planning that delays implementation buys us nothing more than a
> > > smaller window of usefulness.
> > Maybe by then only 64-bit cpus will matter. Who knows.
>
> Reality check.
>
> Embedded PCI 32bit processors are going to be very common
> People are only now retiring 486's
>
> So add another seven or eight years to your estimate

Given a little more context, I thought we were talking specifically
about 64bit-PCI-on-32bit-machines?

Assuming that, AFAICS Ben's statement seems more correct.

And IMHO we definitely should not optimize for 64-bit-on-32-bit case.
Let CONFIG_HIGHMEM grow dma_addr_t to 64-bits, for that case only...

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