Subject: Re: [PATCH] [POWERPC] Fix QEIC->MPIC cascading

From: Anton Vorontsov <[email-masked]>
Date: Thu, 20 Sep 2007 21:41:59 +0400

On Thu, Sep 20, 2007 at 12:03:08PM -0500, Timur Tabi wrote:
> Anton Vorontsov wrote:
>> set_irq_chained_handler overwrites MPIC's handle_irq function
>> (handle_fasteoi_irq) thus MPIC never gets eoi event from the
>> cascaded IRQ. This situation hangs MPIC on MPC8568E.
>
> I'm not familiar with the differences between IPIC and MPIC.  What is this 
> patch not needed for 83xx?

Yup, this patch not needed for 83xx. IPIC doesn't have end()/eoi().
(..and MPIC doesn't have ack()).

Though...

Idially QEIC should do both ack() and end(), at the beginning and at
the end of irq handling respectively.

I don't know (didn't look) why this works for 83xx w/o ack()...
maybe IPIC don't need this. Or maybe there is a bug hiding.

-- 
Anton Vorontsov
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