Re: [alsa-devel] [PATCH] ASoC: da7219: check SRM lock in trigger callback - Pierre-Louis Bossart

From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
To: "Sridharan, Ranjani" <ranjani.sridharan@intel.com>
Cc: "Lu, Brent" <brent.lu@intel.com>,
	Adam Thomson <Adam.Thomson.Opensource@diasemi.com>,
	"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	Support Opensource <Support.Opensource@diasemi.com>,
	Liam Girdwood <lgirdwood@gmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Takashi Iwai <tiwai@suse.com>,
	"Chiang, Mac" <mac.chiang@intel.com>,
	Mark Brown <broonie@kernel.org>,
	Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
	"cychiang@google.com" <cychiang@google.com>
Subject: Re: [alsa-devel] [PATCH] ASoC: da7219: check SRM lock in trigger callback
Date: Tue, 11 Feb 2020 15:12:01 -0600	[thread overview]
Message-ID: <2eeca7fe-aec9-c680-5d61-930de18b952b@linux.intel.com> (raw)
In-Reply-To: <CAFQqKeWHDyyd_YBBaD6P2sCL5OCNEsiUU6B7eUwtiLv8GZU0yg@mail.gmail.com>

On 2/11/20 2:37 PM, Sridharan, Ranjani wrote:
> 
>      > I think the patch is for those systems which enable I2S clocks in
>     pcm_start instead
>      > of pcm_prepare. It has no effect on systems already be able to
>     turn on clocks in
>      > supply widgets or set_bias_level() function.
>      >
>      > If the trigger type in the DAI link is TRIGGER_PRE, then the
>     trigger function of FE port
>      > (component or CPU DAI) will be called before codec driver's
>     trigger function. In this
>      > case we will be able to turn on the clock in time. However, if
>     the trigger type is
>      > TRIGGER_POST, then the patch does not help because just like what
>     you said, codec
>      > driver's trigger function is called first.
> 
>     IIRC we recently did a change to deal with underflows. Ranjani, can you
>     remind us what the issue was?
> 
> Hi Pierre,
> 
> Are you talking about the change in this commit acbf27746ecfa96b
> "ASoC: pcm: update FE/BE trigger order based on the command"?
> 
> We made this change to handle xruns during pause/release particularly on 
> the Intel HDA platforms.

this change was just to mirror the behavior between start/stop, I 
thought there was a patch where we moved to TRIGGER_POST by default?

What I am trying to figure out if whether using TRIGGER_PRE is ok or not 
for the SOF firmware.

Thanks!
-Pierre