[alsa-devel] Boot procudure on HDA driver

[Takashi Iwai]

On Mon, 13 May 2019 11:00:18 +0200,
Kailang wrote:
> 
> Hi Takashi,
> 
> When System Boot up.
> The Hda Driver running step was as below.
> 
> alc_init();
> alc_shutup();
> alc_init();
> 
> The depop procedure was put in spec->init_hook and spec->shutup.
> 
> But I find more codec which run spec->shutup at boot up. It will occur pop noise.
> If it doesn't run spec->shutup, it will not occur pop noise or reduce pop noise.
> 
> How could the spec->shutup not run at boot up?
> 
> I ever test to put the check in spec->shutup() for PM_EVENT_SUSPEND and PM_EVENT_HIBERNATE and shutdown.
> But if power_save=1, it was have issue for this.
> Codec was idle already in power_save=1 state. If system go suspend, it will not run spec->shutup() again.

I guess it's a runtime PM, hence it's neither PM_EVENT_SUSPEND nor
PM_EVENT_HIBERNATE.

Actually, if the shutup procedure makes the problem on a certain
platform, just skip it.  It's an optional behavior and would be fine
without it (of course only if it's confirmed to work :)


Takashi