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Date: Sat, 1 Nov 2014 00:55:14 +0000
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>,
        Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
        Jonathan Corbet <corbet@lwn.net>,
        Dan Williams <dan.j.williams@intel.com>,
        Vinod Koul <vinod.koul@intel.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Alan Stern <stern@rowland.harvard.edu>, linux-pm@vger.kernel.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        dmaengine@vger.kernel.org, Lars-Peter Clausen <lars@metafoo.de>,
        Michal Simek <michal.simek@xilinx.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Subject: Re: [PATCH v8 3/5] amba: Don't unprepare the clocks if device driver
 wants IRQ safe runtime PM
Message-ID: <20141101005514.GY27405@n2100.arm.linux.org.uk>
References: <1413795888-18559-1-git-send-email-k.kozlowski@samsung.com>
 <1413795888-18559-4-git-send-email-k.kozlowski@samsung.com>
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On Sat, Nov 01, 2014 at 01:45:47AM +0100, Rafael J. Wysocki wrote:
> On Monday, October 20, 2014 11:04:46 AM Krzysztof Kozlowski wrote:
> > @@ -198,8 +217,10 @@ static int amba_probe(struct device *dev)
> >  		pm_runtime_enable(dev);
> >  
> >  		ret = pcdrv->probe(pcdev, id);
> > -		if (ret == 0)
> > +		if (ret == 0) {
> > +			pcdev->irq_safe = pm_runtime_is_irq_safe(dev);
> 
> This looks racy.
> 
> Is it guaranteed that runtime PM callbacks won't be run for the device
> after pcdrv->probe() has returned and before setting pcdev->irq_safe?
> If not, inconsistent behavior may ensue.

You are absolutely correct.  So that knocks that idea on its head.

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