linux-kernel - Re: [PATCH] soundwire: fix pm_runtime_get

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Date:   Mon, 8 Apr 2019 07:12:03 +0000
From:   Jan Kotas <jank@...ence.com>
To:     Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
CC:     Jan Kotas <jank@...ence.com>,
        "vkoul@...nel.org" <vkoul@...nel.org>,
        "sanyog.r.kale@...el.com" <sanyog.r.kale@...el.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: Re: [PATCH] soundwire: fix pm_runtime_get_sync return code checks



> On 5 Apr 2019, at 17:04, Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com> wrote:
> 
> On 4/5/19 2:26 AM, Jan Kotas wrote:
>> 
>>  
>>  	ret = pm_runtime_get_sync(slave->bus->dev);
>> -	if (ret < 0)
>> +	if (ret < 0 && ret != -EACCES)
>> 
> There was a patch submitted on 3/28 by Srinivas Kandagatla who suggested an alternate solution for exactly the same code.
> 
> +	if (pm_runtime_enabled(slave->bus->dev)) {
> +		ret = pm_runtime_get_sync(slave->bus->dev);
> +		if (ret < 0)
> +			return ret;
> 
> I am far from an expert on pm_runtime but Srinivas' solution looks more elegant to me.

Hello Pierre,

Please take a look at this patch, that was my inspiration:
https://lists.linuxfoundation.org/pipermail/linux-pm/2011-June/031930.html

I also took a look, and it seems the value returned by 
pm_runtime_get_syncis simply ignored in a lot of places, 
so checking its value may be excessive.

Regards,
Jan