Re: setserial problems...
On Sun, Apr 20, 1997 at 03:17:06PM -0400, Peter Iannarelli wrote:
> > No, it's irq2; I had to set the jumper myself. What you wrote is just the
> > defaults. I ran OS/2 previous to Linux, and you can't share irqs like
> > that under OS/2. :)
> Well all I can tell you is I'm running 4 16450s cua0 to 3.
> When I issue a procinfo irq 2 is assiged to the cascade.
> What the cascade is, I don't know. Irq 3 is set to serial
> and irq4 is set to serial. Linux has the ability to share
> interupts between slow devices like serial ports.
The high interrupts (8-15) are connected to a second IRQ controller
(8259), and that interrupt controller is connected into IRQ 2 of
the first controller, hence "cascade."
On sharing IRQs, my understanding is that the ISA bus is electrically
unable to share IRQs, when both are being used together. Actual
mileage may vary.
Yes, the defaults are 4 3 4 3 respectively but they are just defaults,
and should be changed for concurrent use of the ports. Mine
are 4 3 5 7, with 7 to be changed to 2 when I can next be bothered,
although IRQ printing (to lp1 on IRQ 7) works anyway.
Hamish Moffatt, StudIEAust firstname.lastname@example.org
Student, computer science & computer systems engineering. 3rd year, RMIT.
http://yallara.cs.rmit.edu.au/~moffatt (PGP key here) CPOM: [**** ] 42%
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