Inefficient PCI DMA usage (was: [experimental patch] UHCI updates)

[Johannes Erdfelt]

On Fri, Jan 19, 2001, Miles Lane <[e-mail]> 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