[alsa-devel] Constant noise on HDA ALC275

[Julien Danjou]

On Mon, Oct 08 2012, Takashi Iwai wrote:

> Doesn't the beep work if you load pcspkr module?  It should be there
> independently.

pcspkr is loaded, but no sound from the speakers. And I don't think this
laptop has an old buzzer. ;)

> Hm, then maybe the effect of removing noise appears no matter which
> input of NID 0x0b be unmuted?  

I've retested some, and you're right, it seems some others do make the
noise disappear:

For example, this works too:

@@ -198,7 +198,7 @@
   Control: name="Beep Playback Switch", index=0, device=0
     ControlAmp: chs=3, dir=In, idx=4, ofs=0
   Amp-In caps: ofs=0x17, nsteps=0x1f, stepsize=0x05, mute=1
-  Amp-In vals:  [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80]
+  Amp-In vals:  [0x80 0x80] [0x80 0x80] [0x00 0x00] [0x80 0x80] [0x80 0x80]
   Connection: 5
      0x18 0x19 0x1a 0x1b 0x1d
 Node 0x0c [Audio Mixer] wcaps 0x20010b: Stereo Amp-In


This one too:
@@ -198,7 +198,7 @@
   Control: name="Beep Playback Switch", index=0, device=0
     ControlAmp: chs=3, dir=In, idx=4, ofs=0
   Amp-In caps: ofs=0x17, nsteps=0x1f, stepsize=0x05, mute=1
-  Amp-In vals:  [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x80 0x80]
+  Amp-In vals:  [0x80 0x80] [0x80 0x80] [0x80 0x80] [0x00 0x00] [0x80 0x80]
   Connection: 5
      0x18 0x19 0x1a 0x1b 0x1d
 Node 0x0c [Audio Mixer] wcaps 0x20010b: Stereo Amp-In

Other pairs do not work, but some do change the noise sound.

No pair work when speakers or master is muted; the noise is always
there, no matter which pair I mute/unmute.

> So, obviously muting the amp triggers the noise.
> BTW, does the noise come only from speaker, not from headphone,
> correct?

Yeah correct. Never got any noise in the headphone.
(That's how and why I didn't got insane so far with that noise always
there :)

> Related tests: what happens if you mute both input amps of the node
> 0x0d?  This is a mixer widget between DAC and the speaker pin.
> Does this widget work as a proper mute/unmute point without causing
> noise?

I tried all combinations on 0x0d with master unmuted: there's 2 inputs,
so 4 combinations, and I got… 4 different noises. Almost funny.
If master is muted, changing any input amps from 0x0d change nothing at
all, noise still there.

>> When doing that, I cannot hear anything, because it seems to disconnect
>> the speakers. My idea would be to set this pin to 0x00 instead of 0x40
>> when "Speakers" are set to mute (I don't know about master though).
>> WDYT?
>
> Possible, but a bit hackish.  Let's see...

Heh, too bad. But you know better than me. :)

-- 
Julien Danjou
// Free Software hacker & freelance
// http://julien.danjou.info
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 835 bytes
Desc: not available
URL: <http://mailman.alsa-project.org/pipermail/alsa-devel/attachments/20121008/476d350c/attachment.sig>