Re: IDE controller detection 2.4 +devfs

[Rene Rebe <rene.rebe@gmx.net>]

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!

> 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 ??????

(Maybe I should switch back to Mew as MUA to not let kernel-hackers
see the Sylpheed string in the mail-header :-((()

> The only thing that confuses me is why the secondary onboard channel
> is /dev/ide/host1 rather than /dev/ide/host0/bus1.

Only when disabled in the bios (but PLEASE look at the nice lists above
...)

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


k33p h4ck1n6
  René

-- 
René Rebe (Registered Linux user: #127875 <http://counter.li.org>)

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          rene@rocklinux.org

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