Messages in this thread | | | Date | Sat, 16 Apr 2011 00:39:47 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [RFC PATCH] genirq: implement read_irq_line for interrupt lines |
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On Fri, 15 Apr 2011, Abhijeet Dharmapurikar wrote:
> Thomas Gleixner wrote: > > On Fri, 15 Apr 2011, Abhijeet Dharmapurikar wrote: > > > > > Some drivers need to know what the status of the interrupt line is. > > > This is especially true for drivers that register a handler with > > > IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING and in the handler they > > > need to know which edge transition it was invoked for. > > > > What's the purpose of this? How is that going to be used? > > The main purpose is to know in the handler if it was invoked becuase of a > rising edge or the falling edge.
Come on. That's not an explanation. I know that already and it does not answer my question how this is going to be used. IOW: What does the driver do aside of knowing that it was a rising falling edge?
> Now one could say that the driver should maintain some state and toggle it > upon each invocation of this handler. That scheme quickly goes out of sync > because we might ignore interrupts while suspended.
Suspend is a totaly different issue. I have the impression that you are trying to solve some basic issue at the driver level again - just this time you add some core helper to get it solved.
Can you please show _AND_ explain the code which is going to use this?
Thanks,
tglx
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