linux-kernel - Re: [PATCH 1/3] irq / PM: New driver interface for wakeup interruptsn

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Message-ID: <alpine.DEB.2.10.1408011533580.4997@nanos>
Date:	Fri, 1 Aug 2014 15:43:21 +0200 (CEST)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
cc:	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org,
	Linux PM list <linux-pm@...r.kernel.org>,
	Dmitry Torokhov <dtor@...gle.com>
Subject: Re: [PATCH 1/3] irq / PM: New driver interface for wakeup
 interruptsn

On Fri, 1 Aug 2014, Rafael J. Wysocki wrote:
> OK, I guess "IRQ_HANDLED from a wakeup interrupt" may be interpreted as
> IRQ_HANDLED_PMWAKE.  On the other hand, if that's going to be handled in
> handle_irq_event_percpu(), then using a special return code would save us
> a brach for IRQ_HANDLED interrupts.  We could convert it to IRQ_HANDLED
> immediately then.

We can handle it at the end of the function by calling
note_interrupt() unconditionally do the following there:

      if (suspended) {
      	 if (ret == IRQ_NONE) {
	    if (shared)
	       yell_and_abort_or_resume();
         } else {
	    abort_or_resume();
         }
      }
      if (noirqdebug)
      	 return;
 
> OK, I'll take a stab at the IRQF_SHARED thing if you don't mind.

Definitely not :)

> Here's my current understanding of what can be done for IRQF_NO_SUSPEND.
> 
> In suspend_device_irqs():
> 
> (1) If all actions in the list have the same setting (eg. IRQF_NO_SUSPEND unset),
>     keep the current behavior.
> (2) If the actions have different settings:
>     - Actions with IRQF_NO_SUSPEND set are not modified.
>     - Actions with IRQF_NO_SUSPEND unset are switched over to a stub handler.
>     - IRQS_SUSPEND_MODE (new flag) is set for the IRQ.

Can we please do that in setup_irq() and let the shared ones always
run through the stub? That keeps suspend/resume_device_irqs() simple.

Thanks,

	tglx
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