busdma problem
Andrew Thompson
thompsa at FreeBSD.org
Tue Feb 3 18:00:14 PST 2009
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
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