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From: Hans Petter Selasky <hselasky@c2i.net>
To: Piotr =?utf-8?q?Zi=C4=99cik?= <kosmo@semihalf.com>
Date: Mon, 29 Jun 2009 14:24:45 +0200
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Cc: freebsd-arm@freebsd.org, freebsd-usb@freebsd.org, thompsa@freebsd.org
Subject: Re: CPU Cache and busdma usage in USB
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On Monday 29 June 2009 14:16:13 Piotr Zi=C4=99cik wrote:
> Look for bus_dmamap_sync() sync description, last sentence:
> <cite>
> If read and write operations are not preceded and followed by the
> appropriate synchronization operations, behavior is undefined.
> </cite>

I don't think this is a problem. I do flush read buffers before using them,=
=20
and invalidate them afterwards. Write buffers only get flushed once.

=2D-HPS