Jose Angel Amador Fundora wrote in a message to Mike Bilow:
JAAF> This point is interesting. I have a MS-400 card modified for
JAAF> sharing an interrupt, now it is set for IRQ7, so all four
JAAF> ports share IRQ7. This WORKED with BPQ.
We sold a lot of those. There was a factory version, the MU-400, which was set
up for sharing the same IRQ across all four ports as supplied. (By an odd
coincidence, the nomenclature was that the "U" was the "Unix" model.)
JAAF> My copy of Slackware 3.3 insists on detecting the standard
JAAF> four ports at boot. Later, on a setserial script, I set the
JAAF> proper adresses and IRQ. I needed to use ^fourport.
This is normal.
JAAF> It works OK with ONE PORT on this card. It is 0x3E8, and it
JAAF> has my KPC-2 for the two meters port. When I attempted to
JAAF> put a second port on this card then it stopped working,
JAAF> leaves the STA LED on and refuses to work. So now I am
JAAF> using a four por card for just ONE RF port.
JAAF> I have thought of preparing a small card with dangling wires
JAAF> to attach each 16450 to a free and independent IRQ from 10
JAAF> to 15. I have had no time to do a proper job so far.
JAAF> Must this be that way ? Is there any hidden mistake of mine
JAAF> or using independent IRQ's is the ONLY way out ?
The issue may be your modifications rather than the card or driver. I know of
no reason why an MS-400 properly modified to share one IRQ would have any
problem under Linux. It is important that you modify the hardware so that the
lines are wire-or'ed using diodes and a pull-up resistor rather than floated
high, or the card will be unreliable. We have used both MS-400 and stock
MU-400 cards under Linux with a single IRQ serving all four ports.
-- Mike
