On Tue, 6 Nov 2001, Randy.Dunlap wrote:
> The Intel chipset specs say that PIC1 uses:
> (all hex:) 20-21, 24-25, 28-29, 2c-2d, 30-31, 34-35, 38-39, 3c-3d.
>
> Some of the older chipset specs say that all of these other than
> 20-21 are just aliases of 20-21 (like the 440MX spec).
> Later specs don't say this (as in all of the 800-model ICH0/ICH2
> specs).
These are chipset implementation details (i.e. address decoder's
shortcomings) only. An 8259A only uses two I/O ports; in PC/AT systems,
these are 0x20, 0x21 and 0xa0, 0xa1 for the two PICs, respectively. Since
the 0x00-0xff range is assigned to motherboard devices, there is no
problem with leaving aliases free -- they are never used by Linux. You
still need to verify your extra devices are really present there.
-- + Maciej W. Rozycki, Technical University of Gdansk, Poland + +--------------------------------------------------------------+ + e-mail: macro@ds2.pg.gda.pl, PGP key available +- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Wed Nov 07 2001 - 21:00:31 EST