To: Nathan J. Williams <>
From: Robert.V.Baron <>
List: port-i386
Date: 12/18/1997 21:51:00
I still would claim that IRQ 9 and 11 are safe.  That would give
you enough for the pcic and one card.  I can live with booting 
with only the ethernet in.  (I might try to throw in irq 12, if
you need it -- so you can't use the mouse during install.)

I can also add that I've found ports 0x2a0-2ff pretty safe also.
So that the "install kernel" might use this range to allocate from.
(Ethernet's typically don't use much port space.)

I would like to add to the IRQ mess that some IBM laptops DEFINITELY
don't pass IRQ5 to the mainboard.  I think the 755 and I know that 
an old 560 (w/o the L2 cache) did this.  So for these machines IRQ 5
is out.  I think an old AST/DEC machine might not have passed IRQ 9.

The bottom line is I see no software solution if you don't know the
machine you are running on.  So I'd suggest that the installboot
program be generalized so that you can patch an options area to
specify this type of idiosyncracy.  Then the boot program provides
the info to the kernel and it can do the right thing.
(PS Some (hopefully only old 755's) IBM Laptops, use the ps2-30
floppy convention for the floppy is inserted/removed line.  You
could also specify this info.)

I agree with Perry's earlier point that this is VERY late in the 
release engineering cycle to be playing with significant changes.
On the otherhand, this is also very late in the error of laptops
and pcmcia to not be supporting them.  Sigh.