RE: Any Rules for Behavior of bus numbers changing?

["SHEU,PHILIP (HP-Cupertino,ex3)" <psheu@hp.com>]

Ed,

I don't know of any specific requirements in PCI spec that address your
question. We have seen released drivers from major card vendors that fall
into both categories (those that "hard code" PCI device location at time of
driver installation and those that search for their PCI devices every time
the driver loads). Drivers in the latter category are obviously preferred.
For the former, sometimes BIOS workarounds are implemented to minimize
impact when bridge cards are installed (e.g. by spacing out primary and
secondary bus numbers as programmed in the chipset bridge).

Cheers,
Philip

-----Original Message-----
From: Collins, Edward H [mailto:edward.collins@unisys.com]
Sent: Tuesday, June 11, 2002 10:12 AM
To: pci-sig@znyx.com
Subject: Any Rules for Behavior of bus numbers changing?


We are seeing some cards Windows drivers not work because
their bus number has changed between boot cycles, for instance
when a card with a bridge on it is installed and enumerated before
the card in question. 

Is there anything in the spec about how a driver should be able
to respond when it's card gets located on a different bus than the
one it was on during it's installation?

thanks,  

Ed Collins - Unisys Server Development
25725 Jeronimo,    Mission Viejo, 92691
Phone 949.380.5816      Net2 656.5816
Pager  949.587.2076