port-alpha/40077: pmf_system_shutdown(9) breaks reboot(8) on PWS500au

[njoly%pasteur.fr@localhost]

>Number:         40077
>Category:       port-alpha
>Synopsis:       pmf_system_shutdown(9) breaks reboot(8) on PWS500au
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-alpha-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Dec 01 16:20:01 +0000 2008
>Originator:     Nicolas Joly
>Release:        NetBSD 5.99.4
>Organization:
Institut Pasteur
>Environment:
System: NetBSD thanos.sis.pasteur.fr 5.99.4 NetBSD 5.99.4 (GENERIC-$Revision: 
1.327 $) #28: Mon Dec 1 16:48:13 CET 2008 
njoly%lanfeust.sis.pasteur.fr@localhost:/local/src/NetBSD/obj.alpha/sys/arch/alpha/compile/THANOS
 alpha
Architecture: alpha
Machine: alpha
>Description:
Since 2008/02/28, i cannot reboot my PWS500au machine. When returning to the
SRM console, it loops waiting for the SCSI card to come back:
        waiting for pkc0.7.0.1004.0 to start...
At that time, only a SRM init command, which reset the machine, can make it
boot again.

After some reseach, the problem seems to comes from pmf_system_shutdown(9).
http://mail-index.netbsd.org/source-changes/2008/02/28/msg002955.html
This function tries to stop all devices that are behind PCI busses ...
This stops the SCSI controller which the PWS500au SRM dislike.

No sure about the real fix, but at least removing the pmf_system_shutdown()
call from sys/arch/alpha/alpha/machdep.c:cpu_reboot() make reboot/halt
commands work as expected.
>How-To-Repeat:
Simply reboot the machine and notice that SRM is stuck while waiting for
QLogic 1020 device to come back ...
>Fix:
Please.