From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tomasz Figa <t.figa-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Subject: Re: [PATCH v11 19/27] iommu/exynos: add support for power management
	subsystems.
Date: Tue, 18 Mar 2014 16:33:04 +0100
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To: Cho KyongHo <pullip.cho-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Cc: Linux DeviceTree <devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Ulf Hansson <ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Linux Samsung SOC <linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Kevin Hilman <khilman-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Prathyush <prathyush.k-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, Grant Grundler <grundler-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>, Bartlomiej Zolnierkiewicz <b.zolnierkie-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, "Rafael J. Wysocki" <rjw-LthD3rsA81gm4RdzfppkhA@public.gmane.org>, Linux Kernel <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Sachin Kamat <sachin.kamat-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Linux IOMMU <iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>, Kukjin Kim <kgene.kim-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, Sylwester Nawrocki <s.nawrocki-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>, Varun Sethi <Varun.Sethi-KZfg59tc24xl57MIdRCFDg@public.gmane.org>, Antonios Motakis <a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>, Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>, Linux ARM Kernel <linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>, Rahul Sharma <rahul.sharma-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
List-Id: iommu@lists.linux-foundation.org

On 18.03.2014 12:23, Cho KyongHo wrote:
> On Fri, 14 Mar 2014 17:07:53 +0100, Tomasz Figa wrote:
>> Hi KyongHo,
>>
>> On 14.03.2014 06:10, Cho KyongHo wrote:

[snip]

>>> @@ -677,11 +679,40 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
>>>    	platform_set_drvdata(pdev, data);
>>>
>>>    	pm_runtime_enable(dev);
>>> +	data->runtime_active = !pm_runtime_enabled(dev);
>>
>> Hmm, this seems to be a bit misleading. The field is named
>> runtime_active, but the assignment makes it true if PM runtime is _not_
>> enabled (i.e. inactive). Is this correct?
>>
>
> I agree that it may lead misunderstood.
> data->runtime_active actually indicates if electric power is asserted
> to the System MMU. pm_runtime_enable() call must enable runtime pm
> for the given device. If runtime pm is not enabled although pm_runtime_enable()
> is called, CONFIG_PM_RUNTIME is not configured.
>
> Actually, it is replacible with
> if (IS_ENABLED(CONFIG_PM_RUNTIME))
>      data->runtime_active = true;

I would keep it as !pm_runtime_enabled(dev), but rename the field to 
something more meaningful, like data->is_powered_on.

Best regards,
Tomasz