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Date:      Sun, 23 Aug 2009 15:26:06 -0700
From:      Pyun YongHyeon <pyunyh@gmail.com>
To:        Marius Strobl <marius@alchemy.franken.de>
Cc:        freebsd-sparc64@freebsd.org
Subject:   Re: Audio on Sunblade 100
Message-ID:  <20090823222606.GA1185@michelle.cdnetworks.com>
In-Reply-To: <20090819204603.GL25891@alchemy.franken.de>
References:  <4A7C6B50.3070503@networkz.ch> <20090817205340.GA75477@alchemy.franken.de> <20090817215612.GB75477@alchemy.franken.de> <20090818192748.GA6585@alchemy.franken.de> <20090819175610.GA20481@michelle.cdnetworks.com> <20090819204603.GL25891@alchemy.franken.de>

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On Wed, Aug 19, 2009 at 10:46:03PM +0200, Marius Strobl wrote:

[...]

> > > Ok, I think I've identified the incorrect bus_dma(9) settings
> > > with the help of Tatsuo YOKOGAWA's ali(4) (which as least for
> > > the alignment requirement also matches the NetBSD autri(4). A
> > > new patch is at:
> > > http://people.freebsd.org/~marius/t4dwave_M5451_32-bit.diff
> > 
> > The patch looks good to me but I have two questions. The alignment
> > restriction specified in bus_dma_tag_create(9) really works even
> > if the alignment is greater than PAGE_SIZE? I vaguely remember
> > the alignment was not satisfied last time I tried it on i386 if I
> > specified 256K.
> 
> Hrm, from a quick check of the i386 busdma and the sparc64
> busdma and IOMMU code I see no indication why such an
> alignment shouldn't work as expected, neither do relevant
> man pages like bus_dma(9) and contigmalloc(9) indicate a
> restriction to PAGE_SIZE. Based on the addresses of the
> buffers I get on sparc64 (f.e. 0xc0000000 and 0xc0020000)
> I'd also say it just works. But before possibly commiting
> this change I've to also run-time check it on i386 anyway.
> 

I tried it on amd64 CURRENT and it still fails to align if I set
16K as alignment. So I guess i386 may also have the same issue. As
you said I also wonder why contigmalloc(9) does not honor the
alignment.



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