tomja@InnoTrac.fi (Tom Javen) writes:

>But e.g. a multi port serial card could have 8 16550s connected to the
>same IRQ, so preventing shared irqs would not be a good idea.

But all the multi port serial cards with "interrupt sharing" I have seen
do *not* share ISA bus IRQs.  They all have glue logic that feeds
the individual UARTs IRQ lines to a single ISA IRQ.

Also, the 8250A and up UARTs can't produce real edge triggered interrupts.
They generate level triggered interrupts and the PC interrupt controller
triggers on the front edge of the IRQ signal being asserted.

-- 
Christoph Badura

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