linux-kernel - Re: [RFC PATCH 1/7] DMA: tegra-apb: Correct runtime-pm usage

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Message-ID: <20150824092230.GI13546@localhost>
Date:	Mon, 24 Aug 2015 14:52:30 +0530
From:	Vinod Koul <vinod.koul@...el.com>
To:	Jon Hunter <jonathanh@...dia.com>
Cc:	Laxman Dewangan <ldewangan@...dia.com>,
	Stephen Warren <swarren@...dotorg.org>,
	Thierry Reding <thierry.reding@...il.com>,
	Alexandre Courbot <gnurou@...il.com>,
	dmaengine@...r.kernel.org, linux-tegra@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [RFC PATCH 1/7] DMA: tegra-apb: Correct runtime-pm usage

On Mon, Aug 24, 2015 at 09:47:13AM +0100, Jon Hunter wrote:
> 
> On 23/08/15 15:17, Vinod Koul wrote:
> > On Tue, Aug 18, 2015 at 02:49:09PM +0100, Jon Hunter wrote:
> > 
> >> @@ -1543,7 +1531,7 @@ static int tegra_dma_pm_suspend(struct device *dev)
> >>  	int ret;
> >>  
> >>  	/* Enable clock before accessing register */
> >> -	ret = tegra_dma_runtime_resume(dev);
> >> +	ret = pm_runtime_get_sync(dev);
> > 
> > why is this required ?
> 
> Because the clock could be disabled when this function is called. This
> function saves the DMA context so that if the context is lost during
> suspend, it can be restored.

Have you verified this? Coz my understanding is that when PM does suspend it
will esnure you are runtime resume if runtime suspended and then will do
suspend.
So you do not need to do above

-- 
~Vinod
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