port-i386/42681: NetBSD/i386 fails to find PCI devices under qemu

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         42681
>Category:       port-i386
>Synopsis:       NetBSD/i386 fails to find PCI devices under qemu
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-i386-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 27 18:20:00 +0000 2010
>Originator:     Andreas Gustafsson
>Release:        NetBSD 5.0.1
>Organization:
>Environment:
System: NetBSD guava.gson.org 5.0.1 NetBSD 5.0.1 (GENERIC) #0: Thu Jul 30 
01:39:11 UTC 2009 
builds%b8.netbsd.org@localhost:/home/builds/ab/netbsd-5-0-1-RELEASE/i386/200907292356Z-obj/home/builds/ab/netbsd-5-0-1-RELEASE/src/sys/arch/i386/compile/GENERIC
 i386
Architecture: i386
Machine: i386
>Description:

Booting NetBSD/i386 (e.g., version 5.0.1) under qemu (e.g., version
0.11.1) using qemu's and NetBSD's default ACPI settings will result in
the booted NetBSD not finding the emulated PCI bus nor any PCI
devices.

This particular bug can be worked around using qemu's -no-acpi option,
but then you will run into other bugs instead.  Fixing the default
case (ACPI enabled) would be the preferred fix.  See
http://marc.info/?l=qemu-devel&m=124386233030034&w=2
for some related discussion.

It can probably be debated whether this should be fixed in qemu or in
NetBSD.  My take is that it should be fixed in both, because fixing it
in NetBSD will allow new versions of NetBSD to run under old versions
of qemu, and fixing it in qemu will allow new versions of qemu to run
old versions of NetBSD. I'm initially filing this as a NetBSD bug, but
feel free to also reporting it as a qemu bug.

>How-To-Repeat:

Install qemu from pkgsrc and run the following commands:
  
  ftp 
ftp.netbsd.org://pub/NetBSD/NetBSD-5.0.1/i386/installation/cdrom/boot-com.iso
  qemu -nographic -serial stdio -cdrom boot-com.iso

See that no PCI buses or PCI devices appear in the kernel boot messages.

>Fix: