Re: agp0 hang in 5.2.1-RELEASE

From: Scott Long <scottl_at_freebsd.org>
Date: Fri, 19 Mar 2004 18:12:33 -0700 (MST)
On Sat, 20 Mar 2004, Dag-Erling [iso-8859-1] Smørgrav wrote:
> Scott Long <scottl_at_freebsd.org> writes:
> > On Fri, 19 Mar 2004, Dag-Erling [iso-8859-1] Smrgrav wrote:
> > > set hint.agp.0.disabled="1"
> > I don't see any code in the agp drivers to look at this hint.  Is this
> > impleneted some other way?
>
> Doesn't newbus automatically take care of that?
>
> DES

No.  This has been debated occasionally, but has some landmines.  Newbus
doesn't know what 'agp0' is until the probe bidding is complete. So you
can really only disable the attach, not the probe.  But what if the probe
is destructive or buggy?  You're then left to telling the parent of the
device (usually a bus) to ignore the device.  For PCI, this requires that
the user know the bus, device, and function numbers.  This is
inconvenient, but not impossible.  Unfortunately, this also means that
every bus type might have different identifiers, and no one has come up
with a mechanism yet that can be logically extended to these arbitrary bus
types.

Maybe handling the attach phase and ignoring the probe phase is good
enough for now.  Feel free to propose something =-)

Scott
Received on Fri Mar 19 2004 - 16:08:32 UTC

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