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Subject: Re: [PATCH v6 10/16] dmaengine: tegra-apb: Remove assumptions about
 unavailable runtime PM
To:     Dmitry Osipenko <digetx@gmail.com>,
        Laxman Dewangan <ldewangan@nvidia.com>,
        Vinod Koul <vkoul@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= <mirq-linux@rere.qmqm.pl>
CC:     <dmaengine@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <20200130043804.32243-1-digetx@gmail.com>
 <20200130043804.32243-11-digetx@gmail.com>
From:   Jon Hunter <jonathanh@nvidia.com>
Message-ID: <24ca0a86-032f-2686-4dd2-6e4c5cf60223@nvidia.com>
Date:   Thu, 30 Jan 2020 14:09:02 +0000
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On 30/01/2020 04:37, Dmitry Osipenko wrote:
> The runtime PM is always available on all Tegra SoCs since the commit
> 40b2bb1b132a ("ARM: tegra: enforce PM requirement"), so there is no
> need to handle the case of unavailable RPM in the code anymore.
> 
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/dma/tegra20-apb-dma.c | 10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index 7158bd3145c4..22b88ccff05d 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -1429,11 +1429,8 @@ static int tegra_dma_probe(struct platform_device *pdev)
>  	spin_lock_init(&tdma->global_lock);
>  
>  	pm_runtime_enable(&pdev->dev);
> -	if (!pm_runtime_enabled(&pdev->dev))
> -		ret = tegra_dma_runtime_resume(&pdev->dev);
> -	else
> -		ret = pm_runtime_get_sync(&pdev->dev);
>  
> +	ret = pm_runtime_get_sync(&pdev->dev);
>  	if (ret < 0)
>  		goto err_pm_disable;
>  
> @@ -1546,8 +1543,6 @@ static int tegra_dma_probe(struct platform_device *pdev)
>  
>  err_pm_disable:
>  	pm_runtime_disable(&pdev->dev);
> -	if (!pm_runtime_status_suspended(&pdev->dev))
> -		tegra_dma_runtime_suspend(&pdev->dev);
>  
>  	return ret;
>  }
> @@ -1557,10 +1552,7 @@ static int tegra_dma_remove(struct platform_device *pdev)
>  	struct tegra_dma *tdma = platform_get_drvdata(pdev);
>  
>  	dma_async_device_unregister(&tdma->dma_dev);
> -
>  	pm_runtime_disable(&pdev->dev);
> -	if (!pm_runtime_status_suspended(&pdev->dev))
> -		tegra_dma_runtime_suspend(&pdev->dev);
>  
>  	return 0;
>  }

I wonder if we need to make the pm_runtime_put a pm_runtime_put_sync or
call pm_runtime_barrier() here, to ensure it has called the callback
when freeing the channel? Otherwise this is fine.

Jon

-- 
nvpublic