RELENG_6 power button ignored after halt if ACPI enabled

Nate Lawson nate at root.org
Thu Sep 21 15:29:00 PDT 2006


Wilkinson, Alex wrote:
>     0n Sun, Sep 17, 2006 at 10:29:26PM -0700, Nate Lawson wrote: 
> 
>     >Try setting this sysctl:
>     >sysctl hw.acpi.disable_on_reboot=1
>     >
>     >It may be that you need acpi to stop managing your power button after halt.
> 
> I dont get it ? I thought you needed ACPI to do the actual shutdown ?

He isn't doing halt -p, he's doing "halt", then hitting the power 
button.  If acpi is still enabled, it intercepts the button event but 
can't do anything because the OS is halted (i.e. no shutdown() 
available).  If ACPI is disabled by that point, the BIOS handles it and 
powers off the system.

This only applies to his system, it's not necessarily true in general. 
Some systems won't work if ACPI is disabled during this process, hence 
the sysctl.

Just goes to show how complicated this all is, but it's not MY fault.  :)

-- 
Nate


More information about the freebsd-acpi mailing list