Re: PATCH: IDE - sensible probing for PCI systems

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

On Gwe, 2005-06-24 at 12:52, Maciej W. Rozycki wrote:
>  Well, keyboard and mouse are USB these days, serial and parallel are PCI, 
> floppies are not used anymore and the ISA DMA controller would only be 
> needed for them.  Video?  I've thought ISA implementations are gone -- 
> what is all that AGP/PCI-E noise about then?  And no more ISA slots 
> either.

PC systems have serial at 0x3f8/0x2f8 (lpc bus), almost always PS/2 port
on the mainboard. Timers, interrupt controllers. 

> logic, though, which hasn't been moved elsewhere, indeed.  I think it 
> really belongs to the PCI configuration space somewhere -- probably I/O 
> APICs or host bridges.

As I understand it both Windows XP and Linux x86 still require some of
these ports. There is also a range of ports that are needed _before_ the
PCI bus can be used in order to bootstrap the system, configure ram
timings etc and in some cases adjust the caches.

> > also have ranges of non-PCI decoded space that appears in no PCI bar.
> 
>  That is what surprises me and what my whole consideration is about.  
> It's just I don't see a need for such a setup anymore and for a system 
> with no ISA or EISA bridge I'd expect all that legacy to be gone leaving 
> us with no need to handle implicit resources.  But has any manufacturer 
> produced such an i386 system yet?

Whats the _economic_ incentive to do so ? There basically isnt one.