Re: [PATCH] ASoC: da7219: check SRM lock in trigger callback

From: Mark Brown <broonie@kernel.org>
To: Brent Lu <brent.lu@intel.com>
Cc: alsa-devel@alsa-project.org,
	Support Opensource <support.opensource@diasemi.com>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
	linux-kernel@vger.kernel.org, cychiang@google.com,
	mac.chiang@intel.com
Subject: Re: [PATCH] ASoC: da7219: check SRM lock in trigger callback
Date: Mon, 10 Feb 2020 18:59:05 +0000	[thread overview]
Message-ID: <20200210185905.GD14166@sirena.org.uk> (raw)
In-Reply-To: <1581322611-25695-1-git-send-email-brent.lu@intel.com>

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On Mon, Feb 10, 2020 at 04:16:51PM +0800, Brent Lu wrote:

> Intel sst firmware turns on BCLK/WCLK in START Ioctl call which timing is
> later than the DAPM SUPPLY event handler da7219_dai_event is called (in
> PREPARED state). Therefore, the SRM lock check always fail.
> 
> Moving the check to trigger callback could ensure the SRM is locked before
> DSP starts to process data and avoid possisble noise.

Independently of any other discussion trigger is expected to run very
fast so doesn't feel like a good place to do this - given that we're
talking about doing this to avoid noise the mute operation seems like a
more idiomatic place to do this, it exists to avoid playing back
glitches from the digitial interface during startup.

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