Re: IDE controller detection 2.4 +devfs

From: Richard Gooch (rgooch@ras.ucalgary.ca)
Date: Thu Nov 29 2001 - 21:10:52 EST


Rene Rebe writes:
> On Thu, 29 Nov 2001 18:11:21 -0700
> Richard Gooch <rgooch@ras.ucalgary.ca> wrote:
>
> > But it is actually predictable, isn't it? Think of it this way: the
> > IDE subsystem reserves "slots" (host numbers) for installed hardware.
> > If a piece of hardware is disabled in the BIOS, it doesn't mean that
> > the slot won't be reserved.
>
> It would be nice if it would be that way - se below.
>
> > > (All info from my very first mail ...)
> > >
> > > The other bug is: On a Athlon-600 workstation based on an Irongate
> > > board (Asus-K7M) I have to disable the first (primarry) channel of
> > > the onbaord IDE controller, because it has problem with the UDMA-66
> > > mode. But when I disable this channel, Linux generates a /dev/ide/host1
> > > entry - No host0 entry is there. Sure it works - but sucks, too!
> > > (Generates a very unstable feeling in me ...)
> >
> > The "host0" entry isn't shown, because it is disabled. But to say
> > "when I disable this channel, Linux generates a /dev/ide/host1" isn't
> > correct, and implies a problem where there isn't. The correct way to
> > describe this is:
> > "host0" is my primary onboard IDE controller. It might not appear if I
> > disable it.
> > "host1" is my secondary onboard IDE controller. It has the same name
> > whether or not I disable the primary.
>
> No!!!! On the Althon box:
> - nothing disabled in BIOS:
> /dev/ide/host0/bus0/ - on-board primary channel
> /deV/ide/host0/bus1/ - on-board secondary channel
>
> - when I disable the primary channel I get this:
> /dev/ide/host1/bus1/ - on-board secondary channel
>
> So as you can see it moves!! From host0 to host1!

Oh, fuck! Now I see why you're complaining. Yeah, that is busted. I
don't know why this happens. It may be due to some deep and subtle
workings of the IDE code.

Andre: any idea why this is happening?

> > And this is a Feature[tm]. It means that tomorrow when a shiny new
> > drive arrives, you can plug it into your primary channel and enable
> > the channel in the BIOS. You can then boot without having to fix your
> > /etc/fstab, because /dev/ide/host1 is still pointing to the same
> > devices.
>
> Yes that is a really cool advantage I now for months (over a year!)!
> But here is the next example again:
>
> The K6 server (on-board ALI-Aladin-5 + PCI-Card Promisse controller):
>
> /dev/ide/host0/bus0/ - on-board primary channel
> /dev/ide/host0/bus1/ - on-board secondary channel
> /dev/ide/host2/bus0/ - Promisse primary channel
> /dev/ide/host2/bus1/ - Promisse secondarychannel
>
> So where is host1 ??????

Good question. I wonder what's taking up the "host1" slot?

                                Regards,

                                        Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca
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