Re: Shared edge triggered interrupts

Olivier Galibert (galibert@pobox.com)
Fri, 7 Aug 1998 10:49:22 +0200


On Thu, Aug 06, 1998 at 05:13:43PM -0700, Linus Torvalds wrote:
> Note that shared edge-triggered interrupts _do_ work most of the time. But
> reliable? No.

In theory at least, doing passes over all shared interrupt handlers
until none of them triggers should make it reliable. The only
requirement is that the interrupt line has gone through the down state
before we return from the loop. If we wait between each loop long
enough to ensure the interrupt source clearing effect has gone up to
apic, we're ok.

But then, this has a performance cost and anyway I'm not going to
write code for that (or someone tell me how to test it on a ultra1
under solaris ;-).

OG.

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