[PATCH] [POWERPC] Fix QEIC->MPIC cascading

Anton Vorontsov avorontsov at ru.mvista.com
Fri Sep 21 03:41:59 EST 2007

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()).


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
email: cbou at mail.ru
backup email: ya-cbou at yandex.ru

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