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Date: Sun, 22 Mar 2009 17:54:06 -0400
From: Justin Hibbits <jrh29@alumni.cwru.edu>
To: Marcel Moolenaar <xcllnt@mac.com>
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Cc: freebsd-ppc@freebsd.org
Subject: Re: Apple ATA DMA problems with ATAPI
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On Sun, Mar 22, 2009 at 01:41:18PM -0700, Marcel Moolenaar wrote:
> 
> On Mar 22, 2009, at 11:06 AM, Justin Hibbits wrote:
> 
> > Well, it seems I was bitten by the ATA DMA problems from a few  
> > months back.
> 
> Try disabling DMA for atapi in /boot/loader.conf and enable
> it in /etc/sysctl.conf. For some reason, on my Mac Mini at
> least, it helps to first program PIO and then program *DMA.
> 
> YMMV,
> 
> -- 
> Marcel Moolenaar
> xcllnt@mac.com
> 
> 
> 

It appears hw.ata.atapi_dma is a read-only tunable, so /etc/sysctl.conf has no
effect on it, and only throws a warning about being unable to change it.  It's
working sufficiently as PIO, though.

- Justin