[plug] Power down on halt

[Craig Ringer]

On Sun, 2005-10-09 at 09:53 +0800, Shannon Carver wrote:
> Was a new kernel installed with the new OS upgrade?  By the sounds of 
> it, ACPI/APM have been left out of the kernel, or the user drivers, 
> which allow the computer to shutdown correctly have been left out, or 
> aren't working correctly.

FC4 should use ACPI by default. If you've built a custom kernel, then
it's indeed possible you've left out appropriate power management
support.

If your BIOS is old enough (1999 or so) Linux's ACPI support will flatly
refuse to try to read its ACPI tables and will disable its self. In this
case, however, that permits APM support to be loaded, and I'm fairly
certain FC4 will load and enable APM if ACPI is disabled.

Try:

$ dmesg | grep -i apm

On a system where ACPI has been enabled, you should see:

apm: BIOS version 1.2 Flags 0x03 (Driver version 1.16ac)
apm: overridden by ACPI.

You can also grep the system messages for ACPI, and see if you can find
an indication that it's being disabled for any reason. The command:

$ dmesg | grep -i acpi

will produce quite a bit of output on a normal ACPI system.

If you find that ACPI is being disabled but APM isn't being loaded, try
booting with acpi=off on the kernel command line. Otherwise, maybe post
a summary of the current power management being used, what kernel you're
using, etc and we can see where to go from there.

--
Craig Ringer