Re: ACPI on Tyan Motherboard

On Wednesday 20 August 2003 02:49, John Baldwin wrote:
>
> Here's how it works:  The BIOS/hardware monitor the power button.  When an
> OS tells the BIOS that it is ACPI, then the BIOS doesn't do an instant turn
> off when the power button is pressed, but waits to do so until the power
> button has been held down for 4 seconds.  If the power button after 4
> seconds doesn't work, it's still a hardware problem.  FreeBSD can not fix
> your hardware problem.  When you press the power button with an ACPI OS
> running, the hardware sends an interrupt to the OS.  The OS then shuts down
> and asks the BIOS (via ACPI) to power off the machine.  If the machine
> doesn't physically turn off, it's because your BIOS is screwed up and
> didn't handle the power down command properly.  The fact that the 4 second
> trick (which as above bypasses FreeBSD completely and has the BIOS call
> that power down method itself) produces the same broken results means that
> this bug is in your hardware.
>
> FreeBSD sleeps for a bit when it does a halt -p as a workaround for broken
> IDE disks which claim that writes have hit the media when they are still in
> the disks cache, so that is a separate issue.
>
> If you want more info on ACPI and how it works, feel free to head on over
> to www.acpi.info and read the spec for yourself.

Windows 2000 can shutdown my Tiger 230T in very short time, while FreeBSD
is always timeouted with halt -p.
I dont't think it is hardware or BIOS problem, FreeBSD must be wrong in 
something, just like FreeBSD ATA bug for my Tiger 230T, all OS I have in
hand work fine, only FreeBSD does not.

David Xu