panic on a bios16() call with 6-stable...

[Luigi Rizzo]

in a lab of diskless machines, more or less identical
(2003-2004 vintage, pentium 2.6GHz HTT, intel motherboard,
ich5 chipset...), i see 5 out of 11 machine panicing
on a bios16() call in sys/i386/i386/bios.c.
After a bit of investigation i located the problem
in the bios16() call for the 6th PNP device (on those
boxes), the argument is PNP_GET_DEVNODE, and i am
not sure what other relevant data are necessary to
nail down the problem further.
The system panics with a PC of 70:1023 (i think
it is decimal, but i mightbe wrong).

As a temporary workaround i put some code in the loop
in pnpbios identify to break just before the offending
call (the 6th after 5 successful ones) and can get
to a fully working machine, but obviously would like a better cure.

Any ideas ? maybe we are getting bogus info from
the PnP descriptor and passing them to the bios16 call ?

i tried to enable/disable PnP in the bios but made no difference;
enable/disable the onboard audio also makes no difference.
i tried kernels with/without 'device isa' but no difference either,
the code still runs and panics.

	cheers
	luigi