eric keller ([EMAIL PROTECTED]) wrote:
> We were running the nice example programs from Mirko
> Holler. Looking at parport.c, he calls
> rtl_request_irq(7, handler)
> then he does this:
> outb_p(inb_p(0x21) & (~0x80),0x21); //enable interrupt 7
> outb_p(0x20,0x20);
> //clear in service register
> rtl_hard_enable_irq(7);
>
> This program directly manipulates the interrupt controller
> to enable its interrupt line. does this
> code make sense? or is it redundant?
> eric
For RT-interrupts, the low-level irq handling code works as follows
handler:
mask_interrupt_line
ack_irq_controller
call RT-handler
return_from_interrupt
So if it's needed to receive further interrupts from the device,
one has to explicitely re-enable the interrupt line in the handler.
Michael.
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