linux-kernel - Re: [PATCH 4/4] ASoC: wm8524: Delay some time to follow power up sequency

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Date:   Wed, 22 Feb 2023 12:48:52 +0000
From:   Mark Brown <broonie@...nel.org>
To:     Chancel Liu <chancel.liu@....com>
Cc:     lgirdwood@...il.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, perex@...ex.cz, tiwai@...e.com,
        ckeepax@...nsource.cirrus.com, patches@...nsource.cirrus.com,
        alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 4/4] ASoC: wm8524: Delay some time to follow power up
 sequency

On Wed, Feb 22, 2023 at 07:39:45PM +0800, Chancel Liu wrote:

> +	switch (cmd) {
> +	case SNDRV_PCM_TRIGGER_START:
> +	case SNDRV_PCM_TRIGGER_RESUME:
> +	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
> +		mdelay(wm8524->power_up_delay);
> +		break;

Doing a 100ms busy wait in atomic context does not seem like a great
idea, never mind a 1.5s one.  This shouldn't be done in trigger, it
needs to be done later - digital_mute() might be a better time to hook
in, though longer delays like this are really quite bad.

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