Re: PowerPC PCI DMA issues (prefetch/coherency?)

Arnd Bergmann
2009-06-16T17:44:29Z

On Tuesday 16 June 2009, Scott Wood wrote:
> Chris Pringle wrote:
> > Ah right - that would explain what we're seeing then... Doh. Thought I
> > might have been onto something then. Is there any way to force a cache
> > flush? That'd at least prove it was a caching issue if it resolved the
> > problem.
>
> You could enable CONFIG_NOT_COHERENT_CACHE.

If the whole system is noncoherent, that is the right solution. If the
device is the only one, you can also use dma_alloc_noncoherent() and
flush explicitly with dma_cache_sync().