PCI 2.0/2.1 Compatibility Issue

[Scott Davis <sdavis@Futurex.com>]

We have designed a multifunction PCI Add-In card that is demonstrating a
strange anomaly.  We have the following scenarios:

Scenario 1:

We set the Function 0 HeaderType to 0x80, the Function 1 Header Type to 0x80
and the remaining 6 Header Types to 0x00.  We return 0x00000000 for all
registers that are not implemented.  PCs that support PCI 2.0 correctly
address and access Function 1 and 2 I/O space.  PCs that support PCI 2.1/2.2
incorrectly address and access Function 2 I/O space.

Scenario 2:

We set the Function 0 HeaderType to 0x80, the Function 1 Header Type to 0x00
and the remaining 6 Header Types to 0xff.  We return 0xffffffff for all
registers that are not implemented.  PCs that support PCI 2.1/2.2 correctly
address and access Function 1 and 2 I/O space.  PCs that support PCI 2.0
incorrectly address and access Function 2 I/O space.

Does anyone have an idea about what is going on?

Thanks,

Scott Davis
Vice President
Director of Engineering
Encryption Products Group Manager
Jones Futurex, Inc.
3715 Atherton Rd.
Suite 1000
Rocklin, CA 95765
(916)632-9450 x1323
sdavis@futurex.com
www.futurex.com