Re: PCI DMA to small buffers on cache-incoherent arch

Oliver Neukum
2002-06-09T06:46:06Z

Am Sonntag, 9. Juni 2002 07:29 schrieb David S. Miller:
> From: Roland Dreier <roland@topspin.com>
> Date: 08 Jun 2002 18:26:12 -0700
>
> Just to make sure I'm reading this correctly, you're saying that as
> long as a buffer is OK for DMA, it should be OK to use a
> sub-cache-line chunk as a DMA buffer via pci_map_single(), and
> accessing the rest of the cache line should be OK at any time before,
> during and after the DMA.
>
> Yes.

Does this mean that this piece of memory does have to be declared
uncacheable until DMA is finished ?
How else do you solve th problem of validity during DMA and
especially after DMA ?

Regards
Oliver