Subject: Re: Heads up: i386 MP config change
To: Pavel Cahyna <>
From: Steven M. Bellovin <>
List: current-users
Date: 01/08/2003 16:06:10
In message <>, Pavel Cahyna write
>> I have added code to the i386 port to retrieve MP and interrupt
>> routing info via ACPI. Since this is an alternate method to
>> getting the info from the MP BIOS, I made them both optional.
>Could you please explain briefly what is this ACPI thing and why it is
>useful? I was thinking that autoconfiguration is handled pretty well by
>PCI. Also, linux support for ACPI is AFAIC very minimal, I never compile
>it in linux kernel and I never missed it, so this was a for me a proof that
>it's something totally useless invented by hardvare vendors just to show
>some sign of activity. But seeing you put an effort in implementing it,
>one would think it may be actually good for something ... Could you
>comment, please?

I don't know too much about it; I do know that (a) it's the replacement 
for APM, which will matter for laptops, and (b) on my laptop, at least 
(a Thinkpad T21) the ability to hot-swap batteries and drives from the 
"Ultrabay" will require ACPI support.  I'd *love* to be able to switch 
between my floppy, my CD drive, and my spare battery without rebooting.

		--Steve Bellovin, (me) (2nd edition of "Firewalls" book)