Date: Thu, 2 Mar 2000 11:26:09 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
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To: David Hallberg <david DOT hallberg AT data DOT ing DOT hb DOT se>
cc: djgpp AT delorie DOT com
Subject: Re: Interrupts on EPP-port
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On Wed, 1 Mar 2000, David Hallberg wrote:

> I'm having problem with getting my program to trigger on interrupts
> from the parallel port (EPP-mode)
> it works just fine when triggering from the timer, keyboard, and even
> the networkcard (I have tried to switch IRQ between the networkcard and 
> the parallel port, but it still only trigger in the network card and not
> the parallel port)

Your code, as posted, doesn't enable the appropriate IRQ in the
Interrupt Controller in the initialization code, and your interrupt
handler doesn't EOI the Interrupt Controller before it returns.  So
it's no surprise it isn't working.

The reason it works with the timer and the keybord is because these
IRQs are already enabled during bootstrap.  And the EOI problem didn't
show up because you probably chained to the old handler when you tried
your code with the keyboard and the timer, in which case the old
handler did the EOI for you.