Subject: Re: question on howto use invalidate_dcache_range

From: Dan Malek <[email-masked]>
Date: Thu, 13 Mar 2003 13:39:50 -0500

Roland Dreier wrote:

> Is the following not possible:

That's a problem in any system design.  Consider what would happen
if you had an architecture that was hardware cache coherent.
Software that writes to buffers at any time that is also a
DMA target will result in unpredictable behavior.  The system
design for what you described requires a higher level of
shared memory software synchronization as it is exactly the
unpredictability that has to be prevented in any SMP design.

What you described is a real problem with cache unaligned
buffers that has to be avoided in systems that do not have
hardware cache coherency.

	-- Dan

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