Re: [PATCH 15/17] i2c: omap: always return IRQ_HANDLED

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Thu, Jun 14, 2012 at 04:48:56PM +0530, Shilimkar, Santosh wrote:
> On Thu, Jun 14, 2012 at 3:50 PM, Felipe Balbi <balbi@ti.com> wrote:
> > otherwise we could get our IRQ line disabled due
> > to many spurious IRQs.
> >
> > Signed-off-by: Felipe Balbi <balbi@ti.com>
> > ---
> >  drivers/i2c/busses/i2c-omap.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> > index fc5b8bc..5b78a73 100644
> > --- a/drivers/i2c/busses/i2c-omap.c
> > +++ b/drivers/i2c/busses/i2c-omap.c
> > @@ -1015,7 +1015,7 @@ omap_i2c_isr(int this_irq, void *dev_id)
> >                }
> >        } while (stat);
> >
> > -       return count ? IRQ_HANDLED : IRQ_NONE;
> > +       return IRQ_HANDLED;
> 
> no sure if this is correct. if you have IRQ flood and instead of _actually_
> handling it, if you return handled, you still have interrupt pending, right?

The point of returning IRQ_NONE is to indicate to the interrupt layer that
the interrupt you received was not processed by any interrupt handler, and
therefore to provide a way of preventing the system being brought to a halt
though a stuck interrupt line.

So, if you do process an interrupt, you should always return IRQ_HANDLED
even if you couldn't complete its processing (eg, because you've serviced
it 100 times.)