How to catch interrupt

[Roman Kurakin]

Bruce Evans:

>On Wed, 16 Jun 2004, Roman Kurakin wrote:
>  
>
>>    How to catch interrupt for ISA device before registering handler for it?
>>    
>>
>
>This cannot be done without duplicating lots of interrupt handler
>registration code.  (Actually only a little for a quick MD hack: just
>setidt() to point to an interrupt handler, plus enabling the ICU^WPIC,
>plus changing the normal code to not un-enable the PIC.  npx.c still
>does something like this in RELENG_4.)
>
>However, you may only need to test for pending interrupts.  This can
>be done for isa interrupts using isa_irq_pending() to get a bitmap of
>
It seems that this function is not working for interrupts that were 
already used
by some driver before I call it.

rik

>pending irqs.  See sio.c.  On i386's there are also some newer harder
>to use even less portable interfaces for determining pending irqs.
>See i386/include/intr_machdep.h.
>
>Bruce
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