Memory hole 15-16Mb, how?

Darryl Miles (
Sun, 21 Dec 1997 16:01:34 +0000 (GMT)


I have a multiport serial hardware device I've been developing (toying with)
for Linux, in testing I have configured the ISA card to map itself between
640-1M. This card uses 64Kb of address space here.

I would like to be able to put 4 of these cards into a machine and there
isn't enough space between 640K-1M (after VGA/MDA/Video-BIOS/Motherboard-BIOS
and SCSI-BIOS etc... have all take their cut out of it).

The card can easily be configured to reside anywhere within 0 and 16M. My
motherboard can map out the 15-16Mb region (which I believe is specifically
designed for my purposes). But Linux boots up only finding 15Mb, the
machine has 64Mb.

I wish to be able to tell linux with a command line parameter (much like you
can for IO ports with "region=0x1000,128") that it shouldn't allocate this 1M
to anything itself but allow access to it from ring 0. Maybe by configuring
paging system in some way.


Darryl Miles