> Uh, something like bounce buffers is needed for _ALL_ ISA DMA
> operations, on the Alpha.

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> and doesn't appear "for real" at all for ISA devices.  the only way to
> access system memory via DMA from an ISA device is to set up
> scatter-gather DMA (with the scatter-gather DMA hardware).
> 

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> 	(1) _every_ device which uses ISA DMA on the alpha _HAS_ to
> 		use a "bounce-buffer-like" to map/remap DMA regions,
> 		and

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> Some (most, i'd say) of the current ISA drivers that use DMA just can't
> deal with this sanely.  they just aren't structured well enough to deal
> with it, and don't keep around enough information about the memory they
> use to unmap allocations.
> 

Because of the above statements, I have to ask:
	Do any of the current drivers for ISA DMA cards work on the
Alphas. And furthermore, would any ISA DMA driver written for
the Alpha work on other architectures. (Just a thought)

I believe this whole thread started just because some poor soul wanted to use
his Adaptec 1542 on a machine with more than 16M of RAM (quite unreasonable
of him, if you ask me :). I have not looked at the source code in depth,
But is there any way to modify arch/i386/isa/dma.c, to implement the above
operation, that would satisfy both the Purists as well as the Pragmatists ?

Patrick Arnoux