[alsa-devel] [PATCH] soundwire: fix pm_runtime_get_sync return code checks
Pierre-Louis Bossart
pierre-louis.bossart at linux.intel.com
Mon Apr 8 19:43:47 CEST 2019
On 4/8/19 2:12 AM, Jan Kotas wrote:
>
>
>> On 5 Apr 2019, at 17:04, Pierre-Louis Bossart <pierre-louis.bossart at linux.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
The two patches seems to be identical:
static inline bool pm_runtime_enabled(struct device *dev)
{
return !dev->power.disable_depth;
}
static int rpm_resume()
[...]
else if (dev->power.disable_depth > 0)
retval = -EACCES;
However I am still not clear on why this might fail.
I can only think of one possible explanation: there is no explicit
pm_runtime_enable() in the soundwire code, so maybe the expectation is
that the pm_runtime status is inherited from the parent (in the intel
case the PCI driver), and that's missing in non-intel configurations?
> 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.
But not checking seems careless at best...
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