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

From: Benjamin Herrenschmidt <[email-masked]>
Date: Tue, 21 Nov 2006 07:09:45 +1100

On Mon, 2006-11-20 at 17:56 +0100, Ingo Molnar wrote:
> * Sergei Shtylyov <[email-masked]> wrote:
> 
> > >on PPC64, 'get the vector' initiates an ACK as well - is that done 
> > >before handle_irq() is done?
> > 
> >    Exactly. How else do_IRQ() would know the vector?
> 
> the reason i'm asking is that in this case masking is a bit late at this 
> point and there's a chance for a repeat interrupt.

What do you mean by a bit late ?

You can't mask before you know what interrupt occured so you don't
really have a choice there :-) I'm pretty sure that mask + eoi is what
Apple does on Darwin too though.

Cheers,
Ben.