[alsa-devel] Set eapd to follow stream on or off

[Takashi Iwai]

At Tue, 20 May 2014 15:15:49 +0800,
Kailang wrote:
> 
> Hi Takashi,
> 
> HP machine had pop noise via speaker.
> If EAPD on or off, speaker will have pop noise.
> So, they want to set eapd to follow with stream on or off.

I can apply this as is, but still I wonder whether this results in
other problems.  Doing EAPD on/off there means that it happens far
more often.  For example, what happens if you do like below?

     while true; do
       echo -n > /dev/snd/pcmC0D0p
     done

And, what if the device is resumed from power-saving by an audio
playback?  Immediately after the power up, it'll start the streaming,
so it'll turn on EAPD.

That said, isn't it just a need for some delay before EAPD on/off?


thanks,

Takashi

> 
> Many Thanks.
> 
> BR,
> Kailang
> [2 0000-set-eapd-follow-stream-on-off.patch <application/octet-stream (quoted-printable)>]
>