Re: CVS commit: src/sys/dev/ic

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Wed, Oct 08, 2003 at 08:46:06PM +0200, Frank van der Linden wrote:
> On Wed, Oct 08, 2003 at 06:41:37PM +0000, Charles M. Hannum wrote:
> > 2) A controller+drive older than that will read all-1s.  Therefore it will 
> > fail the 0 test and continue polling.  This is completely harmless.  
> > Because 
> > the drive also is too old to support the slave register shadowing, this 
> > test 
> > would not work for it anyway even if it read the main status register.
> 
> Is that guaranteed? This is fine on i386, but there are architectures
> out there, like macppc, that will fault if you read a non-existent I/O
> address.

The register is supposed to exists, but it may be a write-only register.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 24 ans d'experience feront toujours la difference
--