[alsa-devel] Constant noise on HDA ALC275

[Takashi Iwai]

At Thu, 01 Nov 2012 23:39:52 +0100,
Julien Danjou wrote:
> 
> On Tue, Oct 09 2012, David Henningsson wrote:
> 
> Hi David, Takashi,
> 
> I'm still trying to advance on this! :)
> 
> > So; if everything is muted, it causes some codec bug to appear. If this only
> > happens in the speaker, maybe we should try to reroute the speaker to go
> > 0x02 -> 0x0c -> 0x14 instead of 0x03 -> 0x0d -> 0x14? What will happen if
> > you change 0x14 to take its input from 0x0c instead?
> 
> I just did that using the hda-analyzer tool. I changed 0x14 to uses 0x0c
> as a source, and it's indeed much better. The noise disappear when
> neither master or speaker is muted, and actually the music playback
> sounds better and without the little background noise I still hear on
> low volume level.

Good to hear.  What's the remaining issue?

> Actually, I'm sure it'd be easy to come with a patch, so my question
> would rather be: what's this routing about, and why is 0x0d set up
> instead of 0x0c?

The current parser prefers the line-out as the primary output over the
headphone.  Then it tries to assign from the smaller NID, so 0x0c is
assigned to the line-out (which is the speaker in your case), then
0x0d is to the headphone.

> I'm still trying to find a way to fix the noise when speaker or master
> are muted. No chance so far. :(

Do you mean that the noise is there with rerouting like the above, or
you are asking for a patch to achieve the rerouting?


Takashi