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Subject: Re: [PATCH v2 2/2] dmaengine: tegra210-adma: update system sleep
 callbacks
To:     Jon Hunter <jonathanh@nvidia.com>, <dan.j.williams@intel.com>,
        <vkoul@kernel.org>
CC:     <treding@nvidia.com>, <dmaengine@vger.kernel.org>,
        <linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>
References: <1552455794-24946-1-git-send-email-spujar@nvidia.com>
 <1552455794-24946-2-git-send-email-spujar@nvidia.com>
 <c4d0a061-e435-8a60-0dfc-f8e66c0a9f0b@nvidia.com>
From:   Sameer Pujar <spujar@nvidia.com>
Message-ID: <51f5a49e-f105-604c-130c-fd3d0a07bbc5@nvidia.com>
Date:   Wed, 13 Mar 2019 16:10:44 +0530
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On 3/13/2019 3:58 PM, Jon Hunter wrote:
> On 13/03/2019 05:43, Sameer Pujar wrote:
>> If the driver is active till late suspend, where runtime PM cannot run,
>> force suspend is essential in such case to put the device in low power
>> state. Thus pm_runtime_force_suspend and pm_runtime_force_resume are
>> used as system sleep callbacks during system wide PM transitions.
>>
>> Signed-off-by: Sameer Pujar <spujar@nvidia.com>
>> ---
>>   drivers/dma/tegra210-adma.c | 10 ++--------
>>   1 file changed, 2 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/dma/tegra210-adma.c b/drivers/dma/tegra210-adma.c
>> index 650cd9c..be29171 100644
>> --- a/drivers/dma/tegra210-adma.c
>> +++ b/drivers/dma/tegra210-adma.c
>> @@ -796,17 +796,11 @@ static int tegra_adma_remove(struct platform_device *pdev)
>>   	return 0;
>>   }
>>   
>> -#ifdef CONFIG_PM_SLEEP
>> -static int tegra_adma_pm_suspend(struct device *dev)
>> -{
>> -	return pm_runtime_suspended(dev) == false;
>> -}
>> -#endif
>> -
>>   static const struct dev_pm_ops tegra_adma_dev_pm_ops = {
>>   	SET_RUNTIME_PM_OPS(tegra_adma_runtime_suspend,
>>   			   tegra_adma_runtime_resume, NULL)
>> -	SET_SYSTEM_SLEEP_PM_OPS(tegra_adma_pm_suspend, NULL)
>> +	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
>> +				pm_runtime_force_resume)
>>   };
> Looking at our downstream kernel we use LATE_SYSTEM_SLEEP for these. Any
> reason why you changed this?
I think, I just wanted to replace function calls for system sleep here 
and probably did
not see exactly what we have in downstream kernel at that point. Looking 
at the commit
log in downstream, it might qualify for separate patch.
Let me know if you think, its better to add here.
>
> Cheers
> Jon
>