Date: Sun, 17 Jul 2005 00:50:01 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: nate@root.org Cc: freebsd-current@freebsd.org, harrycoin@qconline.com Subject: Re: mss.c pcm fix to ' attach returned 6 ' load failure for v5.x acpi and up Message-ID: <20050717.005001.38197608.imp@bsdimp.com> In-Reply-To: <42D9DA05.1020806@root.org> References: <20050716.125824.48530425.imp@bsdimp.com> <20050716.131701.124866666.imp@bsdimp.com> <42D9DA05.1020806@root.org>
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In message: <42D9DA05.1020806@root.org>
Nate Lawson <nate@root.org> writes:
: M. Warner Losh wrote:
: > <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
:
: Rather than John's addition of returning an arbitrary CID, can we return
: ~0 or some other obviously invalid HID so that drivers don't start
: depending on the order of CIDs?
That might not be a bad idea. I'm not sure the right thing to do is.
I know this would break at least one sound driver, but I believe that
sound driver is broken anyway.
Warner
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