output on address 0x3BB doesn't work on new PCs (BIOS ?)

[bobz]

hi all

i've got an isa card that "maps" itself at 0x3B8-0x3BB and communicates w/ an application (16 bit, under WFW 3.11) through these addresses.
It works perfectly on old PCs (486, first penthiums): i'm able to read/write at those addresses with in/outport and with debug.

On newer hardware (PenthiumII,...), it doesn't work: i always read 0xFF and no writing is performed... (of course using WFW)

Could it be a BIOS problem ?
Tnx
bobz

[KachiWachi]

Did you try to assign the card resources manually in the Windows Device Manager?

[Rainbow]

It's possible that all writes to 3B0-3BB region are redirected by the chipset to AGP/PCI graphics card and thus they never appear on the ISA bus. Try it with ISA graphics card (without AGP/PCI card).