On Mon, 8 Nov 1999, Richard B. Johnson wrote:
> This should work if you must enable interrupts in the interrupt handler.
>
> static void device_isr (int irq, void *p, struct pt_regs *regs)
> {
> INFO *inf = (INFO *) p;
> if(inf->busy++)
> return;
> while(inf->busy--) /* Check this with interrupts off */
> do_stuff(); /* If necessary with interrupts enabled */
> return;
> }
This doesn't work without an interrupt controller.
You forget that the interrupt has to be acknowledged, so you have to
disable interrupts before this and enable them within do_stuff()
explicitly again, that makes writing interrupt handler more complex and
destroys interrupt perfomance again.
bye, Roman
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