[PATCH] ASoC: dapm: don't call pm_runtime_* on card device

[Tzung-Bi Shih]

On Fri, Jul 24, 2020 at 7:16 PM Mark Brown <broonie at kernel.org> wrote:
>
> On Fri, Jul 24, 2020 at 03:07:31PM +0800, Tzung-Bi Shih wrote:
>
> > Commit 4e872a46823c ("ASoC: dapm: Don't force card bias level to be
> > updated") stops to force update bias_level on card.  If card doesn't
> > provide set_bias_level callback, the snd_soc_dapm_set_bias_level()
> > is equivalent to NOP for card device.
>
> > As a result, dapm_pre_sequence_async() doesn't change the bias_level of
> > card device correctly.  Thus, pm_runtime_get_sync() would be called in
> > dapm_pre_sequence_async() without symmetric pm_runtime_put() in
> > dapm_post_sequence_async().
>
> > Don't call pm_runtime_* on card device.
>
> Why is this a good fix, as opposed to only skipping the set_bias_level()
> bit?

Did you mean: skip to call snd_soc_dapm_set_bias_level() in
dapm_pre_sequence_async() and dapm_post_sequence_async()?

If so, skipping snd_soc_dapm_set_bias_level() won't fix the issue.
The runtime_usage increases in pm_runtime_get() and decreases in
pm_runtime_put().

Besides, snd_soc_dapm_set_bias_level() calls card->set_bias_level()
and card->set_bias_level_post() if any.  Skip to call
snd_soc_dapm_set_bias_level() couldn't be a good idea.  It may change
some existing code behavior.