linux-kernel - Re: [PATCH V2] ARM: OMAP2+: omap_device: maintain sane runtime pm status around suspend/resume

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Date:	Wed, 13 Nov 2013 07:45:12 -0800
From:	Kevin Hilman <khilman@...aro.org>
To:	Nishanth Menon <nm@...com>
Cc:	<balbi@...com>, Tony Lindgren <tony@...mide.com>, <paul@...an.com>,
	<rnayak@...com>, <linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2] ARM: OMAP2+: omap_device: maintain sane runtime pm status around suspend/resume

Nishanth Menon <nm@...com> writes:

> On 11/13/2013 06:51 AM, Felipe Balbi wrote:
>> Hi,
>> 
>> On Tue, Nov 12, 2013 at 05:08:30PM -0600, Nishanth Menon wrote:
>>> diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c
>>> index b69dd9a..f97b34b 100644
>>> --- a/arch/arm/mach-omap2/omap_device.c
>>> +++ b/arch/arm/mach-omap2/omap_device.c
>>> @@ -621,6 +621,7 @@ static int _od_suspend_noirq(struct device *dev)
>>>  
>>>  	if (!ret && !pm_runtime_status_suspended(dev)) {
>>>  		if (pm_generic_runtime_suspend(dev) == 0) {
>>> +			pm_runtime_set_suspended(dev);
>> 
>> don't you have to disable pm_runtime around status changes ? Or is
>> pm_runtime already disabled by the time we get here ?
>
> pm_runtime is already disabled by the time no_irq suspend is invoked.
>
>> 
>>> @@ -634,10 +635,10 @@ static int _od_resume_noirq(struct device *dev)
>>>  	struct platform_device *pdev = to_platform_device(dev);
>>>  	struct omap_device *od = to_omap_device(pdev);
>>>  
>>> -	if ((od->flags & OMAP_DEVICE_SUSPENDED) &&
>>> -	    !pm_runtime_status_suspended(dev)) {
>>> +	if (od->flags & OMAP_DEVICE_SUSPENDED) {
>>>  		od->flags &= ~OMAP_DEVICE_SUSPENDED;
>>>  		omap_device_enable(pdev);
>>> +		pm_runtime_set_active(dev);
>> 
>> ditto, also pm_runtime_set_active() may fail.
>> 
> again, pm_runtime is not yet active here yet - we just restore the pm
> runtime state with which we went down with -> and that is not expected
> to fail either - So, how about just adding a WARN if our expectation
> of balanced operation was somehow broken in the future with changes to
> runtime framework?

And also a note in the changelog (or comment at the WARN) about the
assumption that runtime PM is disabled at this point.

Kevin
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