Re: PCI-X Attributes

["Swapnajit Mittra" <mittra@my-deja.com> (by way of Daniel Weaver <danw@znyx.com>)]

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On Wed, 12 Apr 2000 14:14:58   Amit Shah wrote:
>Hi PCI-X Experts,
>
>In a "PCI to PCI-X" Bridge where the transaction(originating at PCI) is
getting converted from PCI to PCI-X, the PCI-X master makes his own
attributes and drives them on the bus.
>
>But for a PCI-X to PCI-X Bridge, when the transaction(originating on PCI-X
Primary) get initiated on the PCI-X Secondary, can the Bridge drive his own
attributes for that transaction, or should he drive the original attributes
of the initiator. 
>
>If the bridge drives his own attributes on Secondary, then the decoding of
the split completion transaction on secondary would be much simpler.
>
>Help Needed !!
>
>Regards,
>
>Amit Shah
>Design Engr,
>DCM Technologies,
>Austin, USA
>
>

You should pretty much use everything
from the incoming attributes for burst 
and DWORD transactions (except for 
transactions which are of Type 0 config 
ops on secondary). 

PCIX1.0 spec specifically says you should 
not touch NS and RO bits. For a Type 0 config
transaction, you should also put the secondary 
bus number in [7:0] of the attribute.

See pages 44-47 and 60-62 of the PCIX spec
for details.

Hope this helps.
- Swapnajit

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