I have a mediocre ISA card which presents to the system as many as 4 serial
ports, all apparently ns16550a's.  They probe fine; I currently have them
wired for
	0x3e8	irq 5
	0x2e8	irq 10
	0x100	irq 14
	0x180	irq 15
(the addresses were recommended by the board vendor as likely defaults; the
irq's I found to be otherwise unused, since this is a pure-SCSI box for now.)

The initial probe seems to work; in each case, it says something like

com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
com1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
com2 at isa0 port 0x3e8-0x3ef irq 5: ns16550a, working fifo
com3 at isa0 port 0x2e8-0x2ef irq 10: ns16550a, working fifo
com4 at isa0 port 0x100-0x107 irq 14: ns16550a, working fifo
com5 at isa0 port 0x180-0x187 irq 15: ns16550a, working fifo

(note that com0 and com1 are on the motherboard.)

Entries in /etc/ttys look like

tty00   "/usr/libexec/getty std.115200" unknown on local rtscts softcar


If I have one of the add-on ports connected to something (a Psion), I get
	NetBSD/i386 (d
and the line wedges.

If I have a built-in port connected, I get
	NetBSD/i386 (dominion)

	login:

and everything is fine.

Shutdown takes forever because the gettys on these ports are hung.

I've assigned these IRQ's to ISA/EISA (instead of PCI/PNP) in the BIOS.

I'm *almost* totally sure the problem is irq-related; nothing else makes much
sense.  I'm thinking of disabling the on-board ports and assigning one of
those IRQ/memory address combos, but before I do anything drastic, I thought
I'd probe for ideas.

The card was apparently made by one of Acer, "Addonics", or "QuickPath".  I
don't think it's exactly a brand-name thing; looks like very generic
hardware (two chips on it labeled "EPIC".)

-s