linux-kernel - Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs

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Date:	Sat, 23 May 2009 22:14:56 +0200
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	Kim Kyuwon <chammoru@...il.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-pm@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	Ingo Molnar <mingo@...e.hu>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs

On Saturday 23 May 2009, Kim Kyuwon wrote:
> On Sat, May 23, 2009 at 7:29 AM, Rafael J. Wysocki <rjw@...k.pl> wrote:
> > On Saturday 23 May 2009, Kim Kyuwon wrote:
[--snip--]
> >> You changed the really important part of Linux, which may affect most
> >> processor architectures. I think you should be careful. If some of
> >> architectures can't take care of it (they can implement
> >> disable_irq_wake correctly in H/W level, will you revert your changes?
> >
> > No, the changes are not going to be reverted.  In fact things should have been
> > done like this already much earlier.
> >
> > Now, do you have any particular example of a problem related to these changes
> > or is it only a theoretical issue?
> 
> I'd CCing you when I'm sending a mail for this particular example of a example.
> http://markmail.org/thread/fvt7d62arofon5xx

Well, as I said above, reverting the changes that introduced
[suspend|resume]_device_irqs() is not an option, becuase it was the only sane
way to achieve the goal they were added for.  So, we need to fix the wake-up
problem on your platform with the assumption that
[suspend|resume]_device_irqs() are going to stay.

For starters, would it be possible to teach the 'disable' hook of your
platform's interrupt controller not to mask the IRQs that have both
IRQ_WAKEUP and IRQ_SUSPENDED set?  That apparently would work around the
wake-up interrupts problem.

Best,
Rafael
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