beep control

NTDEV
1

I’m trying to use the beep as a tool in testing my driver.
When I call MmMapIoSpace to map the physical port address
0x00000061 (range of one byte), NT returns a different virtual
address every time. I would call MmMapIoSpace followed by
MmUnmapIoSpace, and the returned virtual address increases
by 0x00001000 with every mapping/unmapping cycle. Only
virtual addresses of the form 0xNNNN0061 generate a beep
when I write “0x2f” to that address.

Does anyone have any idea why MmMapIoSpace is returning
different virtual addresses for the same physical port
address?

TIA.
Chris

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2

> When I call MmMapIoSpace to map the physical port address

0x00000061 (range of one byte), NT returns a different virtual
address every time. I would call MmMapIoSpace followed by
MmUnmapIoSpace, and the returned virtual address increases
by 0x00001000 with every mapping/unmapping cycle. Only
virtual addresses of the form 0xNNNN0061 generate a beep
when I write “0x2f” to that address.

MmMapIoSpace is not necessary for 0x61 controller port - it is necessary for
memory-mapped hardware registers only, not for x86-style “ports”.
Just use WRITE_PORT_UCHAR to 0x61 - or maybe pass it through
HalTranslateBusAddress with Internal bus type before
WRITE_PORT_UCHAR.

Max