linux-kernel - Re: [alsa-devel] [RFC PATCH 17/40] soundwire: bus: use runtime_pm_get

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Message-ID: <a1b383b3-7846-3545-38a5-beece3e52849@linux.intel.com>
Date:   Tue, 30 Jul 2019 07:57:46 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     alsa-devel@...a-project.org, linux-pm@...r.kernel.org,
        tiwai@...e.de, gregkh@...uxfoundation.org,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        linux-kernel@...r.kernel.org, vkoul@...nel.org, broonie@...nel.org,
        srinivas.kandagatla@...aro.org, jank@...ence.com,
        slawomir.blauciak@...el.com, Sanyog Kale <sanyog.r.kale@...el.com>
Subject: Re: [alsa-devel] [RFC PATCH 17/40] soundwire: bus: use
 runtime_pm_get_sync/pm when enabled



On 7/30/19 6:21 AM, Andy Shevchenko wrote:
> On Mon, Jul 29, 2019 at 05:07:39PM -0500, Pierre-Louis Bossart wrote:
>> On 7/26/19 2:08 PM, Andy Shevchenko wrote:
>>> On Fri, Jul 26, 2019 at 01:08:57PM -0500, Pierre-Louis Bossart wrote:
> 
>>>> -	if (ret < 0)
>>>> +	if (ret < 0 && ret != -EACCES)
>>>
>>> ...and here, the pm_runtime_put_noidle() call is missed.
>>
>> yes but in the example you provided, they actually do more work than just
>> decrement the device usage counter:
> 
> In their case they would like to do that. You decide what is appropriate call
> in your case.
> 
> My point is, that reference counter in case of error handling should be
> returned back to its value.

Agree on the reference count.
I am however not clear on the next step and 'what is appropriate'.

If pm_runtime_get_sync() failed, then technically the device was not 
resumed so marking it as last_busy+autosuspend, or using a plain vanilla 
put() will not result in any action. I must be missing something here.