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

Takashi Iwai tiwai at suse.de
Tue May 20 09:46:37 CEST 2014

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

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?



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

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