pci to pci bridge in NT4.0

[vision <vision@public3.bta.net.cn>]

Dear Sir:


I am now using the 21052-AB PCI-to-PCI Bridge in our PC-add-on card.
At first, I developed it in the DOS-32 envirenment, and it works
properly.
I can change the 21052's primary PCI config space, such as, setting the
I/O limit and base address window and the memory limit and base address
window. When I try to write the DOS-ok card's Device Driver in NT4.0,
I encounter severe problems. That is.

1. I can find the 21052 and read out its config space, but I can not
change
any bit except the Chip Reset bit in the 40th register.

2. The 21052's ISA Mode Enable bit is set in NT, on the other hand it is
clear
in DOS, Why?

3. In the default state, only the memory window can be use. For I/O
transaction,
because the I/O base address is bigger than the I/O limit address, so it
can not
be used. Is there any way can I use the change the necessary register in
the
21052's PCI config Space?

Would you kind helping me solving the above problems?

Sincerely yours,

Shanfeng Hou


Beijing Vision Tech., CO., Ltd.
No.46, BaiShiQiao Rd.
Haidian District,
Beijing 100081,
P. R. China
Tel: 86-10-62189396
Fax:86-10-62189397
E-mail:vision@public3.bta.net.cn
98.10.15