[OpenBIOS] PCI setup code

Jeff Garzik jgarzik at mandrakesoft.com
Wed Mar 29 18:15:12 CEST 2000

Colin Jensen wrote:
> You can't seriously suggest that the operating system should be able to detect
> the motherboard type automatically!  While in *your* application, you could
> hard code the motherboard setups into Linux, this is generally Not A Solution.

Not motherboard type.  Motherboard chipset type.

> Marcus put it best: "IRQ assignment can't be done in the operating system".  And
> this is for a simple reason: operating systems generally can't be hard-coded to
> a particular motherboard.  And THERE IS NO WAY to automatically detect a
> motherboard type.  NONE.  NADA.  CAN'T GO THERE.  The BIOS, since it is going to
> be *glued* to the motherboard, is a much more reasonable choice for hard
> coding...

You CAN detect a motherboard type, by grepping strings out of the BIOS
ROM.  But that is not the point here.  The motherboard CHIPSET type is
easily detected, generally by a simple PCI vendor/device id match.  

WRT IRQ assignment, Marcus is wrong.  In a hotplug system, the OS _must_
do the assignment.  Even Microsoft knows this[1].  That is why most
modern BIOS ROMs come with interrupt routing tables, which give the OS a
[somewhat] standard method for 

This is also why newer motherboards include a Windows' "IRQ driver" or
similar -- so the --OS-- can talk to your motherboard.


[1] http://www.microsoft.com/hwdev/busbios/pciirq.htm

Jeff Garzik              | Tact is the ability to tell a man 
Building 1024            | he has an open mind when he has a
MandrakeSoft, Inc.       | hole in his head.  (-random fortune)
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