Re: Why no interrupt priorities?

Michael Frank
2004-02-27T13:31:52Z

On Fri, 27 Feb 2004 09:05:48 +0000, Russell King <rmk+lkml@arm.linux.org.uk> wrote:

> On Fri, Feb 27, 2004 at 02:26:31PM +0800, Michael Frank wrote:
>> Is this to imply that edge triggered shared interrupts are used anywhere?
>
> It is (or used to be) rather common with serial ports. Remember that
> COM1 and COM3 were both defined to use IRQ4 and COM2 and COM4 to use
> IRQ3.
>
>> Never occured to me to use shared IRQ's edge triggered as this mode
>> _cannot_ work reliably for HW limitations.
>
> The serial driver takes great care with this - when we service such an
> interrupt, we keep going until we have scanned all the devices until
> such time that we can say "all devices are no longer signalling an
> interrupt".
>
> This is something it has always done - it's nothing new.
>

Sorry, i think the serial driver IRQ is level triggered :)

Regards
Michael