Re: Is there still sufficient reason for hw.ata.atapi_dma being 0 by default?

From: Søren Schmidt <sos_at_DeepCore.dk>
Date: Fri, 30 Jul 2004 15:06:15 +0200
Maxim Sobolev wrote:
> Since high-speed CD-RW/DVD-RW recorders (32x - 52x) are commodity now 
> IMO it makes sense to review hw.ata.atapi_dma default of 0, since 
> apparently PIO mode can't support necessary sustained data transfer 
> rates anymore. For example I had had problems burning RWs on 16-24x with 
> several drives in PIO mode, which gone when I've switched to DMA.

Hmm, things are still messy, but most drives that support UDMA33 can do 
ATAPI dma. However, that is only part of the equation, the chipset has 
its hands in there as well, and unfortunatly there seems to be no good 
way to detect when it works and when it doesnt.

This is more of a decision thing, until now its been decided to have it 
off by default, if there is consensus to change it, I'll just do that 
and only enable dma on udma33 and above (is there any such animals at 
all, I've newer seen an ATAPI device support > UDMA33).

-Søren
Received on Fri Jul 30 2004 - 11:06:29 UTC

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