Subject: Re: IPL_* and IST_* constants
To: Charles M. Hannum <>
From: Chris G Demetriou <Chris_G_Demetriou@UX2.SP.CS.CMU.EDU>
List: tech-kern
Date: 03/18/1996 08:59:06
> The following specifies a standard that ports using the common ISA and
> EISA code must follow.

Not PCI?  it uses them, too...

> The following constants must be defined in <machine/psl.h>, if _KERNEL
> is defined:

How are they brought into scope by drivers?  In other words, what
header do _drivers_ include to get them?  (Or, if it's a bus-specific
header that drivers include, like isavar.h, what does _it_ include?
If it's psl.h directly, should psl.h be idempotent?)

Some other questions:

(1) how can drivers or busses get strings describing the constants, to
    print?  Or is this considered unnecessary?

(2) what 'form factor' must the constants fit in?  I would assume
    'int,' but i'd like to have it written down some place.