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

[Sergei Shtylyov]

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 name.

> 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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