Re: [spi-devel-general] [Patch] Add spi full duplex mode transfer support

[David Brownell]

On Wednesday 30 August 2006 8:56 am, Stephen Street wrote:

> My experiance has shown the most stack allocated transfer buffers are
> not 8 byte aligned and thus use PIO mode.

Of course, providing a transfer buffer on the stack is nonportable;
it's not DMA-safe (especially on systems with dma-incoherent caches!),
while transfer buffers are required to be DMA-safe so that controller
buffers can choose to use DMA for _all_ transfers if they want.

- Dave


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