Messages in this thread | | | From | Oliver Neukum <> | Subject | Re: PCI DMA to small buffers on cache-incoherent arch | Date | Mon, 10 Jun 2002 01:26:15 +0200 |
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Am Sonntag, 9. Juni 2002 10:48 schrieb Russell King: > On Sun, Jun 09, 2002 at 02:33:35AM -0400, Albert D. Cahalan wrote: > > For device --> memory DMA: > > > > 1. write back cache lines that cross unaligned boundries > > What if some of the cache lines inside the DMA region are dirty and... > > > 2. start the DMA > > get evicted now when the CPU is doing something else? > > > 3. invalidate the above cache lines > > 4. invalidate cache lines that are fully inside the DMA > > You really need to: > > 1. write back cache lines that cross unaligned boundries > 3. invalidate the above cache lines > 2. start the DMA > 4. invalidate cache lines that are fully inside the DMA
Starting DMA has to be the very last step.
Regards Oliver
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