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To: harrycoin@qconline.com
From: "M. Warner Losh" <imp@bsdimp.com>
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Cc: freebsd-current@freebsd.org, nate@root.org
Subject: Re: mss.c pcm fix to ' attach returned 6 ' load failure for v5.x
 acpi and up
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<the refs are wrong for this reply>
Nate writes:
> I really think the driver is broken and the API is fine for this.  I 
> don't like the hack of returning a random CID for checks against the 
> HID.  Drivers down the road may come to rely on this and then every BIOS 
> that has a different order for CIDs becomes a potential breakage point.

They alredy do rely on this.  When they support pnp, they call the
ISA_PNP_PROBE routine.  When they don't then your observation doesn't
matter because the order of the IDs doesn't matter: their non-zeroness
does.

> Drivers should not rely on isa_get_logicalid() to determine a boolean 
> "is PNP?"

Actually, that's the interface.  We have to follow it, even if you
think it is stupid.  It is how we do things.  When we don't have a
logicalid, we return 0.  When drivers don't support pnp devices, it
uses the existance of a non-zero pnpid to know the device isn't for
them.  It has been this way since 3.0.

Warner