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Date:      Wed, 11 Apr 2001 02:45:16 +0200 (CEST)
From:      Cyrille Lefevre <root@gits.dyndns.org>
To:        Matthew Emmerton <matt@gsicomp.on.ca>
Cc:        freebsd-stable@FreeBSD.ORG, freebsd-doc@FreeBSD.ORG
Subject:   Re: ATA_ENABLE_ATAPI_DMA gone?
Message-ID:  <200104110045.f3B0jHA45737@gits.dyndns.org>
In-Reply-To: <003301c0c21d$2c4b0cd0$1200a8c0@gsicomp.on.ca> "from Matthew Emmerton at Apr 10, 2001 08:20:10 pm"

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Matthew Emmerton wrote:
> > the ata(4) manual page isn't clear about the difference between
> > hw.ata.ata_dma (where ata-disk.c says ATA disk DMA mode control) and
> > hw.ata.atapi_dma (where atapi-all.c says ATAPI device DMA mode control) ?
> 
> ATA devices are hard disks.
> ATAPI devices are everything else (tape drives, floppy drives - including
> ZIP drives, and CD-ROM and DVD drives).

I was just saying that the documentation isn't clear about that and
I suppose that everybody don't have to look into the code to make the
difference between them. do you understand what I mean. currently,
the manual page entry says :

hw.ata.ata_dma
set to 1 for DMA access 0 for PIO (default is DMA).

hw.ata.atapi_dma
set to 1 for DMA access 0 for PIO (default is PIO).

as you can see, neither the denomination nor the description
say that hw.ata.ata_dma is about disks and hw.ata.atapi_dma
for all other things.

also, why ata_dma and just wc or tags ? to be homogeneous,
the laters would have be named ata_wc and ata_tags.

about tags, is there a software way to know if some drive
is DPTA or DTLA compliant ? what's happen if someone enable
this w/ uncompliant drives ?

CC: -doc

Cyrille.
--
home: mailto:clefevre@poboxes.com   UNIX is user-friendly; it's just particular
work: mailto:Cyrille.Lefevre@edf.fr   about who it chooses to be friends with. 

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