Milan Jurik wrote:
> Hi Garrett,
>
> Garrett D'Amore pÃÅ¡e v po 01. 09. 2008 v 16:52 -0700:
>
>> Steven Stallion wrote:
>>
>>> Ouch, good catch! I just double checked the spec, and you are completely
>>> right, even though LAS powers high on the 8029, it must be set to zero
>>> effectively forcing you to use the 16-bit DMA configuration.
>>>
>>> Looks like I'll have to rework DMA ;)
>>>
>>>
>> If the primary target for this is for emulated devices (i.e. QEMU,
>> Parallels) it may be simpler to skip DMA altogether. (It isn't clear to
>> me that emulated DMA offers a performance win in those situations -- if
>> it does, I'd expect it to be quite minimal. But then again, I'm not
>> sure how painful the logic behind emulated PIO is either.)
>>
>>
>
> DMA improves usually performance significantly in emulators in
> comparison to PIO (you don't need to process PIO so frequently in
> emulator in such cases, processing every PIO takes a lot of cycles,
> where DMA not).
>
Makes sense -- thanks for the data point.
-- Garrett
> Best regards,
>
> Milan
>
>
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