From: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
To: Mikael Pettersson <mikpe@csd.uu.se>, axboe@suse.de
Subject: Re: DMA for ide-scsi?
Date: Sat, 13 Sep 2003 18:25:27 +0200
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On Saturday 13 of September 2003 13:01, Mikael Pettersson wrote:
> On Sat, 13 Sep 2003 08:29:18 +0200, Jens Axboe <axboe@suse.de> wrote:
> >> Actually with 2.6, you no longer need ide-scsi.  You'll need to upgrade
> >> your cdrecord tools and probably your burning GUI, if you use one.  I've
> >> been burning that way for several months now.  (I'm using xcdroast,
> >> though I need to start it with "-n" since I'm using cdrecord 2.01a18.)
> >> This actually works better for me than ide-scsi as for some reason it
> >> uses less CPU.
> >
> >That's because it _is_ faster. It contains no silly memory allocations
> >for the buffer and data copying in the kernel, the data is mapped from
> >the user buffer and DMA'ed directly from there. It also uses DMA where
> >ide-scsi wont.
>
> That begs the question: why won't ide-scsi do DMA?
> I understand you'd rather see it disappear (:->) but since I use
> it for other ATAPI devices as well, I'd like to see it maintained
> and fully operational. Having DMA in ide-scsi would be nice.

ide-scsi maintainer position is available :-).

> (And the concept of using a SCSI API to ATA devices is in itself
> not broken, even if the implementation has some problems.)

It is not broken short-term, however it is broken long-term.

> /Mikael

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