From owner-freebsd-stable  Tue Apr  4 23:43:21 2000
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From: Soren Schmidt <sos@freebsd.dk>
Message-Id: <200004050643.IAA36470@freebsd.dk>
Subject: Re: ata sad combinatorics
In-Reply-To: <3.0.5.32.20000405094647.007c2660@vivaldi> from Sergei Vyshenski at "Apr 5, 2000 09:46:47 am"
To: svysh@pn.sinp.msu.ru (Sergei Vyshenski)
Date: Wed, 5 Apr 2000 08:43:04 +0200 (CEST)
Cc: mike@sentex.net (Mike Tancsa), freebsd-stable@freebsd.org
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It seems Sergei Vyshenski wrote:
> >The old Intel PIIX is know to have DMA problems, I never intended to 
> >support it, but the current code (from luiqi IIRC) was found to be
> >sufficient IF the BIOS did its job right. I seems that we have a 
> >BIOS here that doesn't setup things the way they should be, and the
> >DMA setup fails because of that. Is there any way you could upgrade
> >your BIOS ??
> >
> >-Søren
> >
> 
> After more experiments:
> 1) A pair of any disks are ok as ad0 and ad1, both in dma mode.
> 2) In a pair ad0+ad2, disk ad2 (irrespective of disk make) 
> is not mounted in dma that easy. BUT, if I wait long enough, 
> (about 1 min) it says: 
> "ata1: trying to fallback to PIO mode"
> after which I have ad0 in dma, ad2 in pio, and no further problems.
> 
> Very clever behavior in such a case! 
> Thanks a lot for your response.

You're welcome :)

> Do you know a way to say that I want just PIO for disk ad2?

Use sysctl on the hw.atamodes oid (man ata.4)

-Søren


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