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SubjectInefficient PCI DMA usage (was: [experimental patch] UHCI updates)
On Fri, Jan 19, 2001, Miles Lane <miles@megapathdsl.net> wrote:
> Johannes Erdfelt wrote:
>
> > TODO
> > ----
> > - The PCI DMA architecture is horribly inefficient on x86 and ia64. The
> > result is a page is allocated for each TD. This is evil. Perhaps a slab
> > cache internally? Or modify the generic slab cache to handle PCI DMA
> > pages instead?
>
> This might be the kind of thing to run past Linus when the 2.5 tree
> opens up. Are these inefficiencies necessary evils due to workarounds
> for whacky bugs in BIOSen or PCI chipsets or are they due to poor
> design/implementation?

Looks like poor design/implementation. Or perhaps it was designed for
another reason than I want to use it for.

2.5 is probably where any core changes will happen, if any. But for now
I suspect I'll need to workaround it in my driver.

I should also check architectures other than x86 and ia64.

JE

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