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Date:      Fri, 22 Nov 2002 20:35:46 +0100
From:      Wilko Bulte <wkb@freebie.xs4all.nl>
To:        John Baldwin <jhb@FreeBSD.ORG>
Cc:        cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG
Subject:   Re: cvs commit: src/sys/dev/acpica acpi_pcib_acpi.c
Message-ID:  <20021122203546.A17603@freebie.xs4all.nl>
In-Reply-To: <200211221811.gAMIBD6m073000@repoman.freebsd.org>; from jhb@FreeBSD.ORG on Fri, Nov 22, 2002 at 10:11:13AM -0800
References:  <200211221811.gAMIBD6m073000@repoman.freebsd.org>

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On Fri, Nov 22, 2002 at 10:11:13AM -0800, John Baldwin wrote:

John,

Could any of this cause the panics people were seeing on -stable with
the patchset you provided?

Wilko

> jhb         2002/11/22 10:11:13 PST
> 
>   Modified files:
>     sys/dev/acpica       acpi_pcib_acpi.c 
>   Log:
>   According to the ACPI spec, the bus number of the child PCI bus of a host
>   to PCI bridge can be read be evaluating the _BBN method of the host to PCI
>   device.  Unfortunately, there appear to be some lazy/ignorant/moronic/
>   whatever BIOS writers that return 0 for _BBN for all host to PCI bridges in
>   the system.  On a system with a single host to PCI bridge this is not a
>   problem as the child bus of that single bridge will be bus 0 anyway.
>   However, on systems with multiple host to PCI bridges and l/i/m/w BIOS
>   writers this is a major problem resulting in all but the first host to
>   PCI bridge failing to attach.  So, this adds a workaround.
>   
>   If the _BBN of a host to PCI bridge is zero and pcib0 already exists
>   and is not us, the we use _ADR to look up our PCI function and slot
>   (we currently assume we are on bus 0) and use that to call
>   host_pcib_get_busno() to try and extract our bus number from config
>   registers on the host to PCI bridge device.  If that fails, then we make
>   an evil assumption that ACPI's _SB_ namespace lays out the host to PCI
>   bridges in ascending order and use our pcib unit number as our bus
>   number.
>   
>   Approved by:    re
>   
>   Revision  Changes    Path
>   1.26      +52 -7     src/sys/dev/acpica/acpi_pcib_acpi.c
---end of quoted text---

-- 
|   / o / /_  _   				wilko@FreeBSD.org
|/|/ / / /(  (_)  Bulte				Arnhem, the Netherlands

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