linux-kernel - Re: [PATCH 3/4] ASoC: codecs: wsa883x: mute/unmute PA in correct sequence

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Message-ID: <4b448582-fe11-7f24-36ac-16fd8a22c139@linaro.org>
Date:   Fri, 24 Mar 2023 06:43:40 +0000
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Mark Brown <broonie@...nel.org>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Cc:     tiwai@...e.com, lgirdwood@...il.com, linux-kernel@...r.kernel.org,
        alsa-devel@...a-project.org, johan+linaro@...nel.org,
        steev@...i.org, dmitry.baryshkov@...aro.org
Subject: Re: [PATCH 3/4] ASoC: codecs: wsa883x: mute/unmute PA in correct
 sequence



On 24/03/2023 00:14, Mark Brown wrote:
> On Thu, Mar 23, 2023 at 01:11:11PM -0500, Pierre-Louis Bossart wrote:
> 
>>> The trigger is run in atomic context, can you really write safely to a
>>> SoundWire device there?
> 
>> Mark, I've seen that comment from you several times, and I wonder if I
>> am missing something: the triggers for SoundWire managers and dailinks
>> are typically nonatomic - at least for the Cadence-based solution the
>> trigger is based on a bank switch that may happen with a delay and with
>> a wait_for_completion(). Sending a command over the SoundWire channel is
>> also typically not atomic, there's usually a wait_for_completion() as well.
> 
> Ah, you're setting the nonatomic flag on your links to disable the
> locking.  The default for trigger operations is to run them with local
> interrupts disabled.  It looks like at least some of the Qualcomm stuff
> does that too.
Yes, by default dailinks are marked as nonatomic in Qualcomm case aswell.

--srini