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Date: Tue, 3 Feb 2009 17:59:58 -0800
From: Andrew Thompson <thompsa@FreeBSD.org>
To: Mark Tinguely <tinguely@casselton.net>
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	<200902040009.n1409v7K033380@casselton.net>
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Cc: arm@freebsd.org, sam@freebsd.org
Subject: Re: busdma problem
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On Tue, Feb 03, 2009 at 06:09:57PM -0600, Mark Tinguely wrote:
> >  On Fri, Jan 30, 2009 at 02:07:14PM -0800, Andrew Thompson wrote:
> >  As a test I removed the checking of KENTER_CACHE in
> >  arm/arm/pmap.c:pmap_kenter_internal() so all memory is uncached and now
> >  dma bounces to a stack variable work.
> >
> >  busdma remaps the address nocache into vaddr_nocache pointer and uses
> >  that for the bcopy, obviously arm_remap_nocache() is not working
> >  correctly.
> >
> >  Andrew
> 
> I suspected this was another occurrance of the same cache problem that
> has been mentioned starting about 3 weeks ago. I even was going to ask
> you if it was using arm_remap_nocache().
> 
> I have a new concept patch for the kernel caching issue at:
> 
> 	http://www.casselton.net/~tinguely/arm_pmap_unmanaged.diff
> 
> I am still waiting for a drive to build a -current machine. I will also
> look at any other caching ideas that others have.

FWIW r188112 has fixed this issue for me. I will still be happy to help
test your caching patch for any regressions, etc.


Andrew