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SubjectRe: ->ack_intr in m68k IDE drivers [was: Re: [PATCH 2/5] ide: ->ide_dma_clear_irq() -> ->clear_irq()]
Bartlomiej Zolnierkiewicz wrote:

>>>> It may also be worth considering turning this method into
>>>>test-and-clear, so that we can get the actual IDE interrupt state on
>>>>the chips that implement this...

>>> Probably might add the test_irq() method to be called on
>>>!hwif->waiting_for_dma. Cleraing the status at once seems impractical...

>> Yet this seems what ack_intr() method is doing already...
>> What it does is testing IRQ status and "acknowledging" it (the semantics
>>of "acknowledge" is not clear to me, yet it seems that it's clearing the
>>interrupt latch in the drivers where it's implemented). And the call site of
>>ack_intr() method corresponds to where test_irq() should have been called,
>>so it seems we don't need yet another method and probably didn't even need
>>clear_irq() method in the first place?..

> They have different goals -- the main purpose of ack_intr() (despite its name)
> seems to be testing whether the IRQ is ours,

It does clear some interrupt bit if it sees that IRQ is ours too, hence
the same.

> OTOH in clear_irq() we know that
> already and we just want to clear the pending IRQ status.

There seems to be duplication of functionality b/w ack_intr() and
clear_irq() now...

> So I'm not sure if unification is desirable... though some improvements are
> definitely possibly there (less confusing naming at least)...

>> Bart, could you clarify about how ack_intr() is supposed to work?

> Good question, m68k list would be the best place to look for an answer..

Well, I seem to have been able to infer it from the code...

MBR, Sergei


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