Apple ATA DMA problems with ATAPI

[Marcel Moolenaar]

On Mar 22, 2009, at 2:54 PM, Justin Hibbits wrote:

> 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.
>>
> 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.


Hmmm... I misremembered. Use atacontrol to set the mode:

mini-g4% sudo atacontrol mode acd0 wdma2
current mode = WDMA2

FYI,

-- 
Marcel Moolenaar
xcllnt at mac.com