kern/41703: hangs during powerdown

[mark%ecs.vuw.ac.nz@localhost]

        Note: There was a bad value `' for the field `Priority'.
        It was set to the default value of `medium'.

>Number:         41703
>Category:       kern
>Synopsis:       hangs during powerdown
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Jul 12 11:30:00 +0000 2009
>Originator:     Mark Davies
>Release:        NetBSD 5.0_STABLE
>Organization:
Dept. of Comp. Sci., Victoria Uni. of Wellington, New Zealand.
>Environment:
        
        
System: NetBSD turakirae.ecs.vuw.ac.nz 5.0_STABLE NetBSD 5.0_STABLE 
(ECS_WORKSTATION) #15: Fri Jun 26 10:02:00 NZST 2009 
mark%turakirae.ecs.vuw.ac.nz@localhost:/local/SAVE/build.obj/src/work/5/src/sys/arch/i386/compile/ECS_WORKSTATION
 i386
Architecture: i386
Machine: i386
>Description:
        Currently on my boxes (running 5.0) I see this:

        Dell Optiplex 745's 755's and 760's - approx 50% of the time "halt -p" 
        will successfully power off, the rest of the time hangs after "acpi0: 
        entering state 5"  (these are all twin cpu machines).

        However Dell Latitude laptop (E6400 and D620, both twin cpus) "halt -p"
        always successfully powers off.
>How-To-Repeat:
        "halt -p", observe
        
>Fix:
        Joerg Sonnenberger suggested a patch at 
http://www.netbsd.org/~joerg/cpu.c.diff
        however that results in a 
                panic: cpu_switchto: switching above IPL_SCHED(8)
        on halt.
        

>Unformatted: