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

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Date:	Fri, 01 Aug 2014 16:29:40 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Thomas Gleixner <tglx@...utronix.de>
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 Friday, August 01, 2014 03:43:21 PM Thomas Gleixner wrote:
> 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;

I see.

> > 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.

OK

Rafael

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