Messages in this thread | | | Subject | Re: [RFC] PPC: MPIC: necessary readback after EOI? | From | Scott Wood <> | Date | Wed, 7 Jan 2015 11:04:43 -0600 |
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On Wed, 2015-01-07 at 15:44 +0100, Benjamin Herrenschmidt wrote: > On Mon, 2015-01-05 at 12:10 -0600, Scott Wood wrote: > > It would have been nice if a code comment explained why it was doing the > > readback... I don't see any particular need to wait for EOI completion > > here (unlike when masking). > > The EOI is what causes the MPIC to drop it's EE output to the CPU, if the > EOI is processed too slowly & asynchronously (posted write + 33Mhz MPIC) > we observe cases of spurrious interrupts. We had some macs basically getting > a spurrious irq for every MPIC interrupts...
Shouldn't reading INTACK be what causes the MPIC to drop its EE output?
-Scott
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