Subject: Re: [PATCH] 2.6.18-rt7: PowerPC: fix breakage in threaded fasteoi type IRQ handlers

From: Ingo Molnar <[email-masked]>
Date: Sun, 19 Nov 2006 21:23:48 +0100

* Benjamin Herrenschmidt <[email-masked]> wrote:

> > dont worry, it's -rt only stuff.
> 
> Still, I'm curious :-) Besides, there have been people talking about 
> having -rt work on ppc64 so ...

ok :)

> What do you need an ack() for on fasteoi ? On all fasteoi controllers 
> I have, ack is implicit by obtaining the vector number and all there 
> is is an eoi...

it's a compatibility hack only. Threaded handlers are a different type 
of flow, but often the fasteoi handler is not changed to the threaded 
handler so i changed it to be a threaded handler too.

threaded handlers need a mask() + an ack(), because that's the correct 
model to map them to kernel threads - threaded handlers can be delayed 
for a long time if something higher-prio is preempting them.

	Ingo