Re: Subsystem Vendor ID

["Weng" <wtx@umem.com>]

Hi,
Vendor ID/Subsystem ID  is hardware wired.
Actually there is no feasible hardware method to modify what you wanted to
do.

There is an universal software method to do the thing you wanted to do. But
it is dependent on operating systems users use.

The method is as follows:
1. Find the BIOS function under interested operating system that sends
command to get Vendor ID/Subsystem ID;

2. Write a driver that takes over the BIOS function like this:
    User call-->Your BIOS function -->system original BIOS function -->
return to User call. The driver should take over system original BIOS
function before PCI address allocation is finished.

3. If user call wants Vender ID/Subsystem ID, your BIOS function returns
your designated Vender ID/Subsystem ID and bypasses system original BIOS
function. Transfer all other unrelated calls to system original BIOS
function.

4. Microsoft uses the method everywhere in all Windows operating systems.
The method is called "Subclass" In Visual C++ language.

Weng

Micro Memory Inc.,
Chatsworth, CA 91311, US.


----- Original Message -----
From: Lloyd Bircher <nicad2@yahoo.com>
To: Hayrettin B. Karayaka <karayaka.1@osu.edu>; <pci-sig@znyx.com>
Sent: Monday, July 10, 2000 12:01 PM
Subject: Re: Subsystem Vendor ID


There isn't a way to directly change the values using
PCI configuration cycles.  However, there may be a
"back door" method to write this register using some
other device specific pci configuration register.  I
am not familiar with the chip you are using, but many
PCI devices use a serial EEPROM to provide the IDs you
refer to.  You will have to check the documentation
for your specific chip in order to know which is
appropriate.

Lloyd Bircher

--- "Hayrettin B. Karayaka" <karayaka.1@osu.edu>
wrote:
> Hi,
>
> We are in the process of designing a PCI card and we
> want to change the
> Subsystem Vendor ID. Is there anyway to change
> VendorID/Subsystem Vendor ID
> field in PCI configuration space in a PCI chip ?
>
> Bora
>


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