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Date:      Fri, 22 Nov 2002 16:08:04 -0500 (EST)
From:      John Baldwin <jhb@FreeBSD.org>
To:        Wilko Bulte <wkb@freebie.xs4all.nl>
Cc:        cvs-all@FreeBSD.ORG, cvs-committers@FreeBSD.ORG
Subject:   Re: cvs commit: src/sys/dev/acpica acpi_pcib_acpi.c
Message-ID:  <XFMail.20021122160804.jhb@FreeBSD.org>
In-Reply-To: <20021122203546.A17603@freebie.xs4all.nl>

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On 22-Nov-2002 Wilko Bulte wrote:
> 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?

No.  All this fixes is people on -current who "lose" PCI busses when
using ACPI.  -stable doesn't use the ACPI PCI code because the PCI code
in -stable is very different from the PCI code in -current.

> 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

-- 

John Baldwin <jhb@FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/

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