Re: Serial ports - how to get them to coexist peacefully...
On Sat, Feb 17, 2001 at 03:16:44AM +1100, hogan wrote:
> P133, 48MB RAM, Debian Testing/Unstable (some bits from unstable) 2.2.17 (move
> to 2.4.1 on hold for time being whilst I read Rusty's howtos on netfilter etc.
> :) ).
>
> Have two onboard ports - ttyS0 and ttyS1 (IRQ 4&3 respectively)
> Have an ISA IO card (everything disabled on card save ttyS3 and "lpt3" [dunno
> linux equiv] - reason for ISA - only have half slot, full and VLB IO cards in
> "stockpile" :) )
>
> Have modem on ttyS0
> Switch between mouse and Wyse60 terminal on ttyS1
> Want mouse on ttyS3 but IRQ conflict ttyS1+ttyS3
>
> Can I make the onboard and oncard ttyS's play nice on same IRQ?
> ... or should I play musical jumpers until they're on separate IRQs?
Making onboard serial ports share interrupts is vudu. Basically the
serial port 'hardware' can either hold the interrupt line or let it
'float' when it isn't signalling an interrupt. If it holds the line,
that means the other port can't signal properly, and then more often
then not neither port will work until reset.
All you can really do is try it out to see if it works or not.
> Read something in 2.4.1 kernel config about making serial ports nice to one
> another when on same IRQ.. anything similar in 2.2.x? Should I go to 2.2.18 in
> interim? Will I need a custom compile? ... Will Danger Mouse save Penfold in
> time? :)
You do need to enable sharing serial interrupts.
-- Ferret
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