ISA core vs. ISA card support

ISA core vs. ISA card support

[Eric S. Raymond]

Because the CML2 coodebase is basically buttoned down at this point,
I'm now trying to do a little forward design -- looking for rulebase
cleanups that will get much harder to do once the CML2 rulebase is
dispersed to the care of four-dozen maintainers.

Top of my list is maybe doing something about the ISA config symbol.
There is a declaration in my arch/i386 rules file that looks like this:

# There are PCI-only machines out there, but as of 2.4.0-test1 I'm told
# nobody has tested the kernel with an x86 lacking ISA.  Giacomo Catenazzi
# believes that some motherboard chips use the ISA support code anyway even
# if you don't have an ISA bus.
require X86 implies ISA==y

This is a real problem, because it means that people configuring for 
PCI-only X86 machines (an increasingly common case) are going to see a
whole boatload of ISA-card questions irrelevant to them.  I'd like to
fix this *before* changing it everywhere might imply a turf war, thank you.

There are a couple of ways I could address this in the rulebase. The best
course depends on facts I don't know.  Like, have kernels more recent than
2.4.0-test1 been built without ISA and tested on PCI-only machines?  If
this is known to work reliably, I can remove the above rule and life will
be simpler and happier.

If not, then I need to tghink about splitting the config symbol into ISA 
and ISA_SLOTS and hacking all of the present driver-visibility predicates
to use the latter, with an implication like this

require ISA_SLOTS implies ISA==y
-- 
		<a href="http://www.tuxedo.org/~esr/">Eric S. Raymond</a>

It would be thought a hard government that should tax its people one tenth 
part.	-- Benjamin Franklin

Re: ISA core vs. ISA card support

[Alan Cox]

> # There are PCI-only machines out there, but as of 2.4.0-test1 I'm told
> # nobody has tested the kernel with an x86 lacking ISA.  Giacomo Catenazzi

I have tested on a couple of legacy free boxes. However they still have
what were once ISA devices lurking (IDE initial setup etc). Many PCI only
boxes have serial ports, parallel, floppy, even ISA style audio devices
on the mainboard internal busses

ISA slots I agree is a useful distinction however

Re: ISA core vs. ISA card support

[Eric S. Raymond]

Alan Cox <alan@lxorguk.ukuu.org.uk>:
> I have tested on a couple of legacy free boxes. However they still have
> what were once ISA devices lurking (IDE initial setup etc). Many PCI only
> boxes have serial ports, parallel, floppy, even ISA style audio devices
> on the mainboard internal busses
> 
> ISA slots I agree is a useful distinction however

Thanks, that's helpful.  I'll introduce an ISA_SLOTS private symbol, then.
Later perhaps we can actually make this distinction in C code;  sounds
like it would be a good idea.
-- 
		<a href="http://www.tuxedo.org/~esr/">Eric S. Raymond</a>

The biggest hypocrites on gun control are those who live in upscale
developments with armed security guards -- and who want to keep other
people from having guns to defend themselves.  But what about
lower-income people living in high-crime, inner city neighborhoods?
Should such people be kept unarmed and helpless, so that limousine
liberals can 'make a statement' by adding to the thousands of gun laws
already on the books?"
	--Thomas Sowell

Re: ISA core vs. ISA card support

[Alan Cox]

> Thanks, that's helpful.  I'll introduce an ISA_SLOTS private symbol, then.
> Later perhaps we can actually make this distinction in C code;  sounds
> like it would be a good idea.

There is no value to it in the kernel. ISA bus and magic that looks like
ISA bus but is welded to the motherboard look the same anyway

Re: ISA core vs. ISA card support

[Eric S. Raymond]

Alan Cox <alan@lxorguk.ukuu.org.uk>:
> > Thanks, that's helpful.  I'll introduce an ISA_SLOTS private symbol, then.
> > Later perhaps we can actually make this distinction in C code;  sounds
> > like it would be a good idea.
> 
> There is no value to it in the kernel. ISA bus and magic that looks like
> ISA bus but is welded to the motherboard look the same anyway

OK, noted.
-- 
		<a href="http://www.tuxedo.org/~esr/">Eric S. Raymond</a>

A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders, give
orders, cooperate, act alone, solve equations, analyze a new problem,
pitch manure, program a computer, cook a tasty meal, fight efficiently,
die gallantly. Specialization is for insects.
	-- Robert A. Heinlein, "Time Enough for Love"