linux-kernel - Re: [PATCH] ASoC: tlv320aic32x4: Kernel OOPS while entering DAPM standby mode

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Message-ID: <20190103124554.GS1846@sirena.org.uk>
Date:   Thu, 3 Jan 2019 12:45:54 +0000
From:   Mark Brown <broonie@...nel.org>
To:     b-ak <anur.bhargav@...il.com>
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ASoC: tlv320aic32x4: Kernel OOPS while entering DAPM
 standby mode

On Wed, Jan 02, 2019 at 10:36:33PM +0530, b-ak wrote:
> During the bootup of the kernel, as soon as the DAPM framework kicks in
> it pushes the codec into standy mode.
> 
> The existing TVL320AIC32x4 codec driver doesn't prepare the clock in
> the probe function.
> This leads to an OOPS when the DAPM tries to put it into standy by calling
> clk_disable_unprepare()
> 
> This patch fixes that problem.

This isn't the best way of fixing this because it makes it look like
there's a missing disable in the removal process.  What would be better
would be to do what other drivers do and check to see what state we're
transitioning from before we disable the clock in set_bias_level().  See
drivers like wm8903.c for examples.

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