RE: PC bios recognizing PCI card

[Richard Walter <rwalter@brocade.com>]

-----Original Message-----
> From: Tisani, Mohamad [mailto:MTisani@pericom.com]

> It seems to me that the BIOS in the system should be responsible
> of Counting 2^^25 clocks before starting to configure the PCI Busses 

Correct.  The requirement is that any system software must not
assume that any general device is ready to talk prior to 2^25 clocks
after reset.  So, it must not attempt to access an unknown device
earlier than that.  (An unknown device being one that is in a slot.
If there is a motherboard device that SW knows can accept config
cycles prior to 2^25 clocks, then it is allowed to access that
device.)

> Therefore it should not be a PCI chip's responsibility to ignore
> all PCI Cycles before the 2 ^^25 clocks before accepting cycles 
>
> for example I know that the latest 21150 and 21154 bridge from
> Intel they say that are 2.2 Compliant but they do accept Config
> cycles after 16 clocks.

A device can not take longer than 2^25 clocks before accepting
config cycles.  It can take anywhere from 0 to 2^25 clocks.
And since 16 is between 0 and 2^25, the 21150 & 21154 are
complient (at least to that part of the spec, I can't comment on
complete compliance... :) )

> Mohamad Tisani

-Richard Walter
Note: I speak for myself, not for Brocade Communications.