On Thursday 27 November 2014 23:23:17 Lyra Zhang wrote:
>
> Yes, I saw this way in other serial drivers.
> But, if then, there are two questions for me:
> 1. Why did some serial drivers need an UN_SHARED irq?
A lot of drivers were written before we had shared IRQs, or
were copied from old drivers, or are for hardware that uses
edge-triggered interrupts instead of level-triggered interrupts.
Only level-triggered interrupts can be shared.
> 2. How can we choose a right way?
It never hurts to implement a shared interrupt handler. Only
if you have no way to find out whether the device triggered
the interrupt or not you have to leave out IRQF_SHARED, and then
you won't be able to return IRQ_NONE.
Arnd
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