kern/163905: FreeBSD 9x kernel panic without acpi && event timer

[Oleg Ginzburg]

>Number:         163905
>Category:       kern
>Synopsis:       FreeBSD 9x kernel panic without acpi && event timer
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Jan 08 03:10:09 UTC 2012
>Closed-Date:
>Last-Modified:
>Originator:     Oleg Ginzburg
>Release:        9-RC3, 9-RELEASE, 9-STABLE
>Organization:
>Environment:
FreeBSD gizmo.my.domain 9.0-STABLE FreeBSD 9.0-STABLE #2 r229773: Sat Jan  7 18:36:35 MSK 2012     root at gizmo.my.domain:/usr/obj/usr/src/sys/GENERIC  amd64

>Description:
The system panics with the message
panic: No usable event timer found

KBD: stack backtrace

#0 0xffffffff808680fe at kbd_backtrace+0x5e
#0 0xffffffff80832cb7 at panic+0x187
#0 0xffffffff80b5284b at cpu_initclocks_bsp+0x3cb
#0 0xffffffff807ea0c0 at initclocks+0x20
#0 0xffffffff807e7707 at mi_startup+0x77
#0 0xffffffff807ef71c at btext+0x2c
>How-To-Repeat:
Just boot FreeBSD 9 with ACPI Disabled.
It does impossible boot FreeBSD in Safe mode
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: