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

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Date:	Thu, 07 May 2009 07:13:55 -0700
From:	Kevin Hilman <khilman@...prootsystems.com>
To:	Kim Kyuwon <chammoru@...il.com>
Cc:	Arve Hjønnevåg <arve@...roid.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-pm@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>, OMAP <linux-omap@...r.kernel.org>
Subject: Re: [PATCH] PM: suspend_device_irqs(): don't disable wakeup IRQs

Kim Kyuwon <chammoru@...il.com> writes:

> 2009/5/7 Arve Hjønnevåg <arve@...roid.com>:
>> 2009/5/6 Kim Kyuwon <chammoru@...il.com>:
>>> 2009/5/7 Arve Hjønnevåg <arve@...roid.com>:
>>>> On Wed, May 6, 2009 at 5:16 PM, Kevin Hilman
>>>> <khilman@...prootsystems.com> wrote:
>>>>> "Rafael J. Wysocki" <rjw@...k.pl> writes:
>>>>>
>>>>>> On Wednesday 06 May 2009, Kevin Hilman wrote:
>>>>>>> Kevin Hilman <khilman@...prootsystems.com> writes:
>>>>
>>>>> There is at least one problem with that which is why Kyuwon Kim added
>>>>> the ->disable hook to OMAP's irq_chip.  The problem is with drivers
>>>>> that call disable_irq() in their suspend hook, usually done to prevent
>>>>> the device from waking the system since on OMAP, any IRQ can be
>>>>> configured to wake the system.
>>>>>
>>>>
>>>> This does not sound correct. disable_irq_wake should be used for this.
>>>> A driver may need to mask its interrupt before suspending but this
>>>> should not also disable it as a wakeup source.
>>>
>>> I wish I could use disable_irq_wake(), but it doesn't work in OMAP.
>>
>> This does not sound like a hardware problem.
>
> We may need advices of TI engineers.
> However, as far as I know, It is impossible to disable 'interrupt
> wake-up' with interrupt enabled. Because an interrupt itself generate
> a system wake-up event in OMAP3430 (Hardware level).

Interrupt wakeups can be disabled at the PRCM level.  Or more simply
we can keep a mask of wakeup-enable interrupts and use that.

I will experiment with getting disable_irq_wake() working.

Kevin

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