Re: [PATCH] 2.6.18-rt7: PowerPC: fix breakage in threaded fasteoitype IRQ handlers
From: Benjamin Herrenschmidt
Date: Sun Nov 19 2006 - 15:41:54 EST
> This is not implicit -- CPU has to read INTACK reg. on OpenPIC.
Which is what I meant... "implicit by reading the vector".
> Really implicit method is in action on x86 where CPU issues dual ACK bus cycle to get
> the vector form 8259...
Which you can do on OpenPIC too. It's the same idea. The concept that
obtaining the vector performs the ack.
> > EOI is a more "high level" thing that some "intelligent" PICs that
> > automatically raise the priority do to restore the priority to what it
> > was before the interrupt occured.
>
> Thank you, I know. Even 8259 has the notion of priority and EOI works the
> same way here.
Ok, so why would you need an ack there then while eoi is just what you
need ? :-)
Also, that's interesting what you are saying about 8259... I should be
able to convert ppc's i8259 to use fasteoi too...
Ben.
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