Re: No Subject

From: Daniela Engert (
Date: Sun Aug 04 2002 - 10:40:07 EST

On Sun, 4 Aug 2002 13:28:46 +0000 (UTC), Henning P. Schmiedehausen

>Bartlomiej Zolnierkiewicz <> writes:
>>On 4 Aug 2002, Alan Cox wrote:
>>> On Sat, 2002-08-03 at 23:16, Bartlomiej Zolnierkiewicz wrote:

>>> > Just rethough it. What if chipset is in compatibility mode?
>>> > Like VIA with base addresses set to 0?
>>> If we found a register that was marked as unassigned with a size then we
>>> would map it to a PCI address. That would go for BAR0-3 on any PCI IDE
>>> device attached to the south bridge.
>>In compatibility mode IDE chipsets have IO at legacy ISA ports and
>>PCI_BASE_ADDRESS0-3 are set to them or to zero (at least on VIA).
>>And they can't be programmed to any other ports (unless native mode).

>this sounds like a problem that I have with the ServerWorks OSB5
>chipset. I actually have PCI_BASE_ADDRESS0-3 at 0 and
>Does this hold true here, too? Or is this VIA specific?

PCI IDE controller chips in compatibility mode may exhibit the
following BAR0-3 values (sorted by likelihood of occurance):

most likely: BAR0-3 are all zero
rare : BAR0-3 show the legacy IDE port values
very rare : BAR0-3 contain garbage

In fact, the best strategy is to *ignore* BAR0-3 in compatibility mode
because they have no meaning then!


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