5.25 floppy drive attached to a D875PBZ

I'm trying to connect an "old" (1990) 5.25" 1.2Mb floppy drive unit
to a D875PBZ original Intel motherboard.

It is the only floppy connected to the floppy onboard controller
as "A:" unit: it is connected through a standard five sockets
floppy 34 pin controller cable, after the "twist" obviously.

The BIOS motherboard seems to support 5.25 1.2M floppy units.

The problem is that the floppy motor do not start at system boot
and the floppy do not work at all.

I already tried to reconnect the 5.25" floppy unit to another
system and it works like a charm (through an old ISA floppy controller.
A 3.5" 1.44Mb floppy unit works without problem when connected
with the same cable to the D875PBZ onboard floppy controller.

Anybody knows if the I/O D875PBZ controller (SMSC LPC47M172) actually
supports 5.25" 1.2M floppy drives?

Thank in advance for any help you may provide to me, Regards
G. Vitillaro.

P.S. Please direct e-mail messages to "giuseppe@no-spam-vitillaro.org"
after removing the "no-spam-" protection string.