Re: Multifunction Add-In Cards and PCI BIOS Enumeration

[Steve Blightman <steve@alacritech.com>]

I've seen this behavior before - if the BIOS sees the multi-function bit for the
first device, ii checks all of the other 7 possible devices.  If the hardware
responds with anything other than Master Abort, the BIOS assumes these devices
exist.  I don't know anything about the QuickLogic device, but I suspect it is
returning data for the other six configuration spaces (probably zeros?).  Maybe
someone from QuickLogic can confirm this for you.  I know of no good way around
it other than to get your card not to respond to the nonexistent configuration
space accesses  (generating Master Abort).  I suspect, by the way, your card
will still work fine in the system - it's just an annoyance probably.

Steve
.
Scott Davis wrote:

> I've designed a multifunction PCI Add-In card that uses the QuickLogic
> QL5130 ESP for the bus interface.  The card has two functions so I've
> created two configuration register sets -- one for each function.  When the
> PC BIOS enumerates the bus, it reports that the card has been found and then
> lists 8 functions -- the first two functions correctly and then 6 unknown
> functions.  I've set the MSB of the Header byte for both functions.  My
> questions are as follows:
>
> Has anyone seen this type of behavior before?
> How do I suppress the listing of the 6 unknown functions?
> Should I be setting the MSB of both header bytes?
>
> Thanks,
>
> Scott