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Message-ID: <7ea278b4-ecd4-bd17-4550-3f6f9136260e@linaro.org>
Date: Fri, 1 Nov 2019 17:22:04 +0000
From: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
robh@...nel.org, vkoul@...nel.org
Cc: devicetree@...r.kernel.org, alsa-devel@...a-project.org,
bgoswami@...eaurora.org, linux-kernel@...r.kernel.org,
spapothi@...eaurora.org, lgirdwood@...il.com, broonie@...nel.org
Subject: Re: [alsa-devel] [PATCH v4 2/2] soundwire: qcom: add support for
SoundWire controller
On 01/11/2019 16:39, Pierre-Louis Bossart wrote:
>
>>>> +static int qcom_swrm_prepare(struct snd_pcm_substream *substream,
>>>> + struct snd_soc_dai *dai)
>>>> +{
>>>> + struct qcom_swrm_ctrl *ctrl = dev_get_drvdata(dai->dev);
>>>> +
>>>> + if (!ctrl->sruntime[dai->id])
>>>> + return -EINVAL;
>>>> +
>>>> + return sdw_enable_stream(ctrl->sruntime[dai->id]);
>>>
>>> So in hw_params you call sdw_prepare_stream() and in _prepare you
>>> call sdw_enable_stream()?
>>>
>>> Shouldn't this be handled in a .trigger operation as per the
>>> documentation "From ASoC DPCM framework, this stream state is linked to
>>> .trigger() start operation."
>>
>> If I move sdw_enable/disable_stream() to trigger I get a big click
>> noise on my speakers at start and end of every playback. Tried
>> different things but nothing helped so far!. Enabling Speaker DACs
>> only after SoundWire ports are enabled is working for me!
>> There is nothing complicated on WSA881x codec side all the DACs are
>> enabled/disabled as part of DAPM.
>
> that looks like a work-around to me? If you do a bank switch without
> anything triggered, you are most likely sending a bunch of zeroes to
> your amplifier and enabling click/pop removals somehow.
>
> It'd be worth looking into this, maybe there's a missing digital
> mute/unmute that's not done in the right order?
Digital mute does not help too, as they get unmuted before
sdw_enable_stream() call in trigger, I hit same click sound.
Same in the disable path too!
Also I noticed that there are more than 20+ register read/writes in the
sdw_enable_stream() path which took atleast 30 to 40 milliseconds.
I will try my luck checking the docs to see if I can find something
which talks about this.
--srini
>
>>
>>>
>>> It's also my understanding that .prepare will be called multiples times,
>>
>> I agree, need to add some extra checks in the prepare to deal with this!
>>
>>> including for underflows and resume if you don't support INFO_RESUME.
>>
>>>
>>> the sdw_disable_stream() is in .hw_free, which is not necessarily
>>> called by the core, so you may have a risk of not being able to recover?
>>
>> Hmm, I thought hw_free is always called to release resources allocated
>> in hw_params.
>>
>> In what cases does the core not call this?
>
> yes, but prepare can be called without hw_free called first. that's why
> we updated the state machine to allow for DISABLED|DEPREPARED ->
> PREPARED transitions.
>
>>>> +static const struct dev_pm_ops qcom_swrm_dev_pm_ops = {
>>>> + SET_RUNTIME_PM_OPS(qcom_swrm_runtime_suspend,
>>>> + qcom_swrm_runtime_resume,
>>>> + NULL
>>>> + )
>>>> +};
>>>
>>> Maybe define pm_runtime at a later time then? We've had a lot of race
>>> conditions to deal with, and it's odd that you don't support plain
>>> vanilla suspend first?
>>>
>> Trying to keep things simple for the first patchset! added this
>> dummies to keep the soundwire core happy!
>
> If you are referring to the errors when pm_runtime is not enabled, we
> fixed this is the series that's been out for review for 10 days now...
>
> see '[PATCH 03/18] soundwire: bus: add PM/no-PM versions of read/write
> functions', that should remove the need for dummy functions.
>
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