small note to GENERIC for isa dependency

Bruce M Simpson bms at
Tue Apr 20 07:14:52 PDT 2004

On Tue, Apr 20, 2004 at 06:03:27PM +0400, Roman Kurakin wrote:
> >The problem is that ISA and the i386 architecture are still intimately
> >involved. It's probably hidden away as something called LPC on yours. :-)
> I only want to say that this is normal wish to remove device "isa" as a
> "hardware missing in my modern box", cause I open it and see nothing
> except PCI slots.

Appearances can be deceiving. I can understand the source of your confusion.
Let me attempt to clarify.

ISA is there in some form. If your machine has legacy hardware of any kind,
such as an AT-PIC programmable interrupt controller, a PS/2 mouse port, or
even a keyboard controller, you need ISA support, even if the devices are
probed via ACPI.

Many machines have PCI slots and not ISA slots, but ISA is still present;
many VIA and Intel based motherboards have a SuperIO chip connected to
the south bridge via what is known as the LPC (Low Pin Count) bus, which is
covered by Intel specifications; this is essentially an ISA bus with less

Only a truly legacy-free machine (and most machines which are i386 and
claim to be legacy-free are not) could live without the isa bus support
in FreeBSD, and to the best of my knowledge, these don't exist yet.

It is with us for the forseeable future.

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