[alsa-devel] [PATCH 1/2] ASoC: rt5670: Revert Keep sysclk on patch

[Mark Brown]

On Mon, Mar 09, 2015 at 12:13:04PM +0000, Bard Liao wrote:

> System clock is needed for rt5670 jack detection function. Usually,
> the system clock source is from MCLK. But some platform such as
> Intel BSW will turn off MCLK in idle mode. So rt5670 need to switch the
> system clock source to its internal clock. The action is done by machine
> driver.

OK...  but if this is the case why does your patch not update any
machine drivers?

> There is a PLL power in rt5670. It should be on if we want to use
> PLL as the system clock source. So we call force enable/disable pin
> in rt5670_set_dai_sysclk. However, cht_bsw_rt5672.c call
> snd_soc_dai_set_sysclk in platform_clock_control which is the dapm
> event of "Platform Clock" widget. In that case,
> snd_soc_dapm_disable_pin and snd_soc_dapm_sync are called
> within a dapm event. I think it is not valid.

This is very unusual, normally such system clock reconfiguration would
be done in the set_bias_level() callback not in a DAPM event.  Doing it
in a DAPM event sounds unreliable as there are only weak guarantees
about the state of the system.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 473 bytes
Desc: Digital signature
URL: <http://mailman.alsa-project.org/pipermail/alsa-devel/attachments/20150309/eec9d9e3/attachment.sig>