Re: [PATCH v7 2/5] genirq: Add handle_fasteoi_{level,edge}_irq flow handlers.

On Wed, 16 Aug 2017, David Daney wrote:

On 08/14/2017 03:25 AM, Thomas Gleixner wrote:

quoted

On Wed, 9 Aug 2017, David Daney wrote:

quoted

  #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY

Can we please make them conditional in order not to bloat all kernels with
it? Like we do for handle_edge_eoi_irq() ?

Yes.  Because these are initially used by exactly one driver, I could just
make it conditional on that driver being enabled.

Alternately, I could invent a new Kconfig symbol to gate these and select that
when the driver is enabled.

Do you have a preference?

The latter.

quoted

Hmm. That's quite different to the way we handle edge interrupts
normally. See handle_edge_irq() and handle_edge_eoi_irq().

Yes, these are not standard edge interrupts.  If they were, I wouldn't need
new handlers.

For this particular irqdomain hierarchy, I need exactly handle_fasteoi_irq()
semantics with the addition of a call to the chip->irq_ack() function *before*
the handler is called.  I chose to "clone" and enhance handle_fasteoi_irq(),
rather than adding hooks with runtime checks to the existing
handle_fasteoi_irq().  There is code bloat this way, but a smaller risk of
breaking other things.

Any additional "stuff" that is not needed to cover this use case would just be
adding dead code.  In the future, if there is a need to enable more users of
these functions, I would not object to doing more.

Ok, so we might rename that thing to something else than edge() as all
edge handlers have this processing loop which is required not to lose
edges.

Thanks

	tglx