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

From: Sergei Shtylyov <[email-masked]>
Date: Mon, 20 Nov 2006 20:03:29 +0300

Hello.

Ingo Molnar 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.

    How's that? Acknowledge != EOI on OpenPIC (as well as 8259).
    Acknoledging sets the bit in the in-service register preventing all the 
interrupts with same or lower prioriry from being accepted.

> 	Ingo

WBR, Sergei